bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of oxidative potential water as a root canal irrigant
Authors: Hata G. , Hayami S. , Weine F. S. , Toda T.
Published: March 2003

Aim

The aim of this study was to evaluate the effectiveness of oxidative potential water (OPW) as an irrigant, based on its ability to remove the smear layer and/or debris from instrumented root canals.

Methodology

One hundred and twenty root canals from extracted human maxillary incisors were instrumented using a conventional step‐back technique with irrigation from sodium hypochlorite (NaOCl) or oxidative potential water (OPW). After instrumentation, the canals were irrigated by syringe or ultrasound using 15% EDTA or OPW as an irrigant. The volume of each irrigant used for syringe irrigation was 10, 20, and 30 mL, respectively, whilst the duration for ultrasonic irrigation was 1, 3, and 5 min, respectively. After irrigation, each root was split longitudinally in two with cutting pliers, and the specimens were prepared for SEM observation. The presence of debris and smear layer on each canal wall was assessed using a three‐point scale for each parameter.

Results

Smear layer was effectively removed with EDTA both introduced via syringe and via ultrasonic irrigation. A similar effect was observed with OPW via syringe irrigation following instrumentation with 5% NaOCl. The canal walls in any of these cases showed open and patent dentinal tubules following smear layer removal. Some specimens irrigated with EDTA exhibited the effect of demineralization on the dentine resulting in funnelling of tubule orifices. Syringe irrigation was more effective in smear layer removal, except for ultrasonic irrigation with 15% EDTA, whilst ultrasonic irrigation was more effective in debris removal including the use of OPW as irrigant following instrumentation with 5% NaOCl. Neither syringe nor ultrasonic irrigation with OPW following instrumentation with OPW removed smear layer or debris effectively.

Conclusions

The most effective irrigation technique for smear removal was 15% EDTA irrigation by means of syringe following instrumentation with 5% NaOCl solution. However, the most effective irrigation technique for debris removal was ultrasonic irrigation regardless of irrigant used. OPW irrigation by means of syringe following instrumentation with 5% NaOCl showed a similar effect to that of 15% EDTA irrigation for removal of smear layer and debris.
In vitro cytotoxicity of a composite resin and compomer
Authors: Quinlan C. A. , Zisterer D. M. , Tipton K. F. , O'Sullivan M. I.
Published: March 2003

Aim This work was designed to investigate the potential cytotoxicity of two of the newer dental restorative materials, Spectrum® composite resin and Dyract® AP compomer.

Methodology Cultured human endothelial cells (ECV‐304) were exposed to each of the restorative materials through a 70‐µm dentine barrier to simulate the in vivo clinical situation. Cell viability was measured by the MTT (3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5 diphenyltetrazolium bromide) assay and lactate dehydrogenase release assay. The effects of different extents of light‐curing were also examined by microscopic examination of stained human promyelocytic leukemia cells (HL‐60). Caspase‐3 activation was determined as a measure of apoptotic cell death.

Results Assessment of cellular viability indicated that both materials cause cell death, with Spectrum® being the more toxic. The cytotoxicity was considerably increased in the absence of the dentine barrier. Direct exposure to Spectrum® for 12 h resulted in the death of 69% of the cells after full light‐curing (78% of total death was by apoptosis) and 96% after partial light‐curing (73% of total death was by necrosis). Assessment of caspase activation, in the absence of the dentine barrier, showed that longer curing‐times resulted in an increase in the proportion of the cells dying through apoptosis, rather than necrosis, for both materials tested.

Conclusions These results indicate the restorative materials to be potentially toxic, particularly if the degree of light‐cure is inadequate.
Prevalence of yeasts in saliva and root canals of teeth associated with apical periodontitis
Authors: Egan M. W. , Spratt D. A. , Ng Y.‐L. , Lam J. M. , Moles D. R. , Gulabivala K.
Published: March 2003

Egan MW, Spratt DA, Ng Y‐L, Lam JM, Moles DR, Gulabivala K. Prevalence of yeasts in saliva and root canals of teeth associated with apical periodontitis. International Endodontic Journal, 35, 321–329, 2002.

Aims To determine: (i) the relative prevalence and diversity of yeasts in salivary and root canal samples from the same patients; and (ii) the clinical factors associated with their presence in saliva and root canals.

Methodology Sixty root canal samples from teeth associated apical periodontitis and the corresponding whole unstimulated saliva samples were obtained from 55 patients. The medical history including antibiotic therapy and clinical/radiographic data on the teeth were recorded. The samples were serially diluted and cultured on yeast & fungi‐selective sabouraud dextrose agar. Isolates were characterized and speciated by the germ tube formation test, hyphal morphology and a commercial biochemical test kit (Rapid ID32C® system).

Results Twenty‐three yeast isolates were recovered from 19 saliva samples and eight isolates from six root canal samples. Candida albicans (17/23 & 3/8) and Rodotorula mucilaginosa (2/23 & 4/8) were the most prevalent isolates from saliva and root canal samples. It was significantly (13.8 times) more probable that yeasts would be recovered from root canals when they were also present in the saliva (P = 0.021). The effect of coronal restoration leakage (P = 0.08) and previous root canal treatment (P = 0.123) were equivocal. The history of antibiotic therapy had no association with the presence of yeasts in saliva (OR = 1.1).

Conclusions Yeasts occurred relatively infrequently (10%) in root canals. Their presence in root canals was significantly associated with their presence in saliva. The role of yeasts in the initiation and perpetuation of periapical disease remains to be determined.
Papilla base incision: a new approach to recession‐free healing of the interdental papilla after endodontic surgery
Authors: Velvart P.
Published: March 2003

Aim The purpose of the present study was to describe and evaluate a new incision technique: the papilla base incision.

Methodology Twenty healthy patients referred for surgical treatment of persisting apical periodontitis, who were free of periodontal disease and had intact interdental papillae were included in the study. The preoperative papilla height was recorded by measuring the distance between the contact point and the most coronal point of the papilla. The papilla base flap, consisting of the papilla base incision and two releasing incisions, was used to expose the bone. The papilla base incision consisted of a shallow first incision at the base of the papilla and a second incision directed to the crestal bone, creating a split thickness flap in the area of the papilla base. Further apically a full thickness flap was raised. Following standard root‐end resection and filling, flap closure was achieved with microsurgical sutures. The papilla base incision was sutured with 2–3 interrupted sutures, which were removed 3–5 days after the surgery. The experimental sites were evaluated at the conclusion of the surgery, at suture removal and after 1 month, and compared to the preoperative findings. The healing pattern, complications and postoperative recession were recorded. The experimental sites were observed with a × 3 magnification and graded as to whether a visible scar resulting from the incision could be detected. Twenty experimental sites were analysed.

Results Complete closure of the wound was achieved in all cases after surgery. Except for four patients with delayed healing at suture removal, all other patients displayed rapid healing. No noticeable space was created beneath the contact point area. The change in distance between the reference point and the most coronal point of the papilla comparing the preoperative and the one‐month postoperative situation was 0.05 ± 0.39 mm. The probing depth remained within normal limits. One month postoperatively, observation of the incision demonstrated: four sites with a visible incision line (grade 1), in seven sites the incision defect could be partially detected (grade 2) and nine incisions could not be detected (grade 3).

Conclusions In patients with healthy marginal periodontal conditions the papilla base incision allows rapid and predictable recession‐free healing following marginal surgical exposure of the soft tissues. One month postoperatively the majority of the incisions were completely or partially invisible. Long‐term healing will be studied.
Characterization of mouse epididymal acrosin: comparative studies with acrosin from boar and human ejaculated spermatozoa
Authors: SUTER  , HABENICHT
Published: March 2003

Acrosin is an acrosomal protease believed to play a major role in fertilization. It is synthesized as an inactive precursor, proacrosin, which is processed via (auto)proteolysis into active form(s). In this paper, comparative studies on the characteristics of acrosin from mouse, boar and human are reported. The mouse proacrosin/acrosin was especially investigated to clarify whether or not the enzyme undergoes modifications during epididymal maturation. Acrosomal extracts from mature and immature mouse spermatozoa, as well as from ejaculated boar and human spermatozoa, were analysed by means of SDS–electrophoresis, Western blot and activity measurements. The studies showed that epididymal maturation produced a shift in the molecular weight of proacrosin. It was also observed that the activation kinetics differ strongly between the three species studied. Human proacrosin showed a constant substrate turnover, acrosin from boar showed sigmoidal activation kinetics and mouse acrosin, either from the caput or the cauda epididymides, showed a rapid decay in activity, suggesting the presence of an endogenous specific inhibitor.
Paternal transmission of genetic damage: findings in animals and humans
Authors: Brinkworth Martin H.
Published: March 2003

The concept that mutations can be induced in the male germ‐line and result in adverse effects in the offspring has achieved only limited acceptance despite considerable theoretical appeal. This is partly because fetal malformations are generally perceived to be induced solely as a result of maternally mediated events during gestation and partly because the low incidence of the end‐points concerned make experimental approaches costly and time‐consuming. Nonetheless, a substantial body of work relating to the hypothesis has accumulated in the last 20 years, which has never been reviewed in its entirety. A consideration of the available evidence indicates that preconceptional paternal exposure to mutagens (particularly radiation, cyclophosphamide and ethylnitrosourea) can indeed, under certain conditions, have adverse effects on offspring. The results suggest two principal mechanisms by which such effects may be induced: the induction of germ‐line genomic instability or the suppression of germ cell apoptosis.
Aneuploidy in spermatozoa of infertile men with teratozoospermia
Authors: HÄrkönen Kati , Suominen Jyrki , LÄhdetie Jaana
Published: March 2003

Recent studies have shown that aneuploidy in spermatozoa of infertile men with poor semen quality is increased. The purpose of this study was to determine whether poor sperm morphology is associated with the incidence of spermatozoa with numerical chromosome abnormalities. Semen samples from 20 infertile teratozoospermic men were studied using multicolour fluorescence in situ hybridization (FISH). Men were divided into four groups according to the proportion of normal sperm morphology: infertile men with <10% (group A, n=7), 10–19% (group B, n=6), and 20–29% (group C, n=7) of morphologically normal spermatozoa, and controls (group D, n=5) with ≥30% normal forms. Two hybridizations were performed. All the samples were analysed using probes for chromosomes 1 and 7 and, in addition, in group A and in controls with normal semen parameters probes for chromosomes X, Y and 18 were also used. Ten thousand spermatozoa were scored per hybridization. Severely teratozoospermic men (<10% normal forms) had significantly higher frequency of disomy 7, 18, YY, XY and diploidy in their spermatozoa when compared with controls. The results suggest that poor sperm morphology is associated with numerical chromosome abnormalities of spermatozoa. Severely teratozoospermic men may be at an increased risk of producing aneuploid offspring.
Embryological consideration of drainage of the left testicular vein into the ipsilateral renal vein: analysis of cases of a double inferior vena cava
Authors: Itoh Masahiro , Moriyama Hiroshi , Tokunaga Yo , Miyamoto Kensaku , Nagata Wakashi , Satriotomo Irawan , Shimada Kazuyuki , Takeuchi Yoshiki
Published: March 2003

The right gonadal vein (GV=testicular vein in men, ovarian vein in women) usually drains into the inferior vena cava (IVC) while the left gonadal vein drains into the left renal vein (RV). This anatomical difference induces relatively weak haemodynamics in the left testicular vein (TV) and is considered to be a cause of a left varicocele. In textbooks on embryology, it has been documented that bilateral supracardinal veins (=origin of right and left IVC) and the subcardinal sinus (=origin of RVs and GVs) symmetrically develop during early embryogenesis. However, persistence and regression of the right and left supracardinal veins, respectively, results in drainage of the left GV into the ipsilateral RV. A double IVC (DIVC) commonly originates from a failure of disappearance of the left supracardinal vein. Although there have been a considerable number of case reports on DIVC, little attention has been paid to the anatomy of the left GV in such cases. We report here an autopsy case, a 72‐year‐old Japanese man, with a DIVC. This case belongs to type BC of McClure and Butler’s classification. In this case, it was observed that the right TV drained into the confluence of the right IVC with the ipsilateral RV, while the left TV drained into the left RV in spite of the presence of the left IVC. This case indicates that the embryonic anastomosis point between the subcardinal sinus and the supracardinal vein on the left side is different from that on the right side. Statistical analysis of many case reports of DIVC also suggests that the bilateral supracardinal veins tend to asymmetrically anastomose with the subcardinal sinus during embryogenesis. These data imply that drainage of the left GV into the ipsilateral RV leads to regression of the left supracardinal vein but also to asymmetrical anastomosis between the supracardinal veins and the subcardinal sinus.
Interactive effect of semen and cervical mucus quality on postcoital test outcome: analysis from an andrological point of view
Authors: Francavilla F. , Romano R. , LA Verghetta G. , Bontempo G. , Santucci R. , Necozione S. , Francavilla S.
Published: March 2003

This study analysed the relationship between semen quality and the postcoital test (PCT) outcome in 616 couples, especially focusing on the interactive effect of semen and cervical mucus quality. When PCTs performed in the presence of unfavourable mucus were excluded, a significant correlation was found between semen parameters and PCT outcome. In oligo/asthenozoospermia, 46.7% of PCT outcomes were negative, while the remaining were positive. Notably, in the presence of an optimal mucus score, 39% of PCT outcomes were good (≥7 forward motile spermatozoa/high power field). In normozoospermia, 16% of PCT were negative. A suboptimal cervical mucus quality significantly affected the PCT outcome in the presence of oligo/asthenozoospermia, but not in normozoospermia.

In couples with repeated PCT, a better mucus score was associated with a significant improvement of the PCT outcome. When the outcome of two PCTs performed in the same couples with an unmodified mucus score was compared, a good consistency of the results was observed. In conclusion, the PCT can provide information in additional to that obtained from conventional semen analysis, as the interactive effect of semen/cervical mucus cannot be accurately inferred from the separate evaluation of the two members of a couple.
Interstitial fibrin‐fibronectin deposition with T cell infiltrates precedes fibrosis in murine viral myocarditis
Authors: Kishimoto Chiharu , Kitazawa Mikio , Takada Hitoshi
Published: March 2003

This study was carried out to investigate interstitial fibrin and fibronectin deposition and subsequent myocardial connective tissue abnormalities in BALB/c‐nu/ + (euthymic and normal T cell function) and BALB/c‐nu/nu (athymic and T cell‐deficient) mice. Both types of mice were inoculated with encephalomyocarditis virus and sacrificed periodically. Sections of the hearts were stained with haematoxylin‐eosin, trichrome, lymphocyte subsets, silver impregnation, and fibrin or fibronectin. In addition, myocardial collagen concentration was measured. Interstitial fibrin and fibronectin appeared in parallel with inflammatory T lymphocytes and myocardial necrosis in the BALB/c‐nu/ + mice. The changes increased until 14 days, subsequently decreasing with time. Interstitial fibrosis and abnormal reticulin fibres were absent until 7 days postinfection, and then increased with time until 60 days. In BALB/c‐nu/nu mice, in contrast, although myocardial necrosis and fibrin‐fibronectin deposition associated with immature T lymphocytes were evident on days 7 and 14, subsequent myocardial fibrosis and reticulin fibre abnormalities were minimal on days 30 and 60. In BALB/c‐nu/ + mice, myocardial collagen concentration increased on day 30, but it did not in BALB/c‐nu/nu mice. Thus, interstitial fibrin‐fibronectin deposition resulting from virus‐induced and T lymphocyte‐mediated myocyte necrosis precedes the subsequent development of interstitial fibrosis and abnormal reticulin architectures in this model of murine myocarditis.
The effect of non‐antihypertensive doses of angiotensin converting enzyme inhibitor on myocardial necrosis and hypertrophy in young rats with renovascular hypertension
Authors: Matsubara  , Matsubara  , Franco  , Padovani  , Janicki
Published: March 2003

In renovascular hypertensive rats, low doses of angiotensin converting enzyme (ACE) inhibitors have been found to prevent myocardial hypertrophy independent of blood pressure level. This finding would suggest humoral rather than mechanical control of myocyte growth. The aim of this study was to examine the effect of nonantihypertensive doses of ACE inhibitor on myocardial hypertrophy and necrosis in hypertensive rats. Renovascular hypertension (RHT) was induced in four‐week‐old Wistar rats. Twenty‐eight animals were treated for four weeks with three doses of ramipril (0.01, 0.1 or 1.0 mg/kg/day, which are unable to lower blood pressure. Fourteen animals were not treated (RHT group). A sham operated, age/sex‐matched group was used as control (n = 10). Myocardial histology was analysed in 3 μm thick sections of the ventricle stained with either haematoxylin‐eosin, reticulin silver stain or Masson's trichrome. There was a significant correlation between systolic blood pressure and left ventricular to body weight ratio in both sets of animals: untreated plus controls and ramipril‐treated rats. ACE inhibition prevented myocyte and perivascular necrosis and fibrosis in a dose‐dependent manner. We conclude that myocardial hypertrophy in rats with renovascular hypertension is directly related to arterial pressure, and that this relationship is not affected by nonantihypertensive doses of ACE inhibitor. Myocardial necrosis/fibrosis and coronary artery damage induced by angiotensin II are prevented by ACE inhibitor in a dose‐dependent manner, despite the presence of arterial hypertension.
Delayed toxicity of cyclophosphamide on the bladder of DBA / 2 and C57BL / 6 female mouse
Authors: ANTON ELSA
Published: March 2003

The present study describes the delayed development of a severe bladder pathology in a susceptible strain of mice (DBA/2) but not in a resistant strain (C57BL/6) when both were treated with a single 300 mg/kg dose of cyclophosphamide (CY). Inbred DBA/2 and C57BL/6 female mice were injected with CY, and the effect of the drug on the bladder was assessed during 100 days by light microscopy using different staining procedures, and after 30 days by conventional electron microscopy. Early CY toxicity caused a typical haemorrhagic cystitis in both strains that was completely repaired in about 7–10 days. After 30 days of CY injection ulcerous and non‐ulcerous forms of chronic cystitis appeared in 86% of DBA/2 mice but only in 4% of C57BL/6 mice. Delayed cystitis was characterized by infiltration and transepithelial passage into the lumen of inflammatory cells and by frequent exfoliation of the urothelium. Mast cells appeared in the connective and muscular layers of the bladder at a much higher number in DBA/2 mice than in C57BL/6 mice or untreated controls. Electron microscopy disclosed the absence of the typical discoidal vesicles normally present in the cytoplasm of surface cells. Instead, numerous abnormal vesicles containing one or several dark granules were observed in the cytoplasm of cells from all the epithelial layers. Delayed cystitis still persisted in DBA/2 mice 100 days after treatment. These results indicate that delayed toxicity of CY in female DBA/2 mice causes a bladder pathology that is not observed in C57BL/6 mice. This pathology resembles interstitial cystitis in humans and could perhaps be used as an animal model for studies on the disease.
Modelling average concentrations of salt and salt substitute in partial or total volumes of semihard cylindrical cheeses
Authors: Zorrilla Susana E. , Rubiolo Amelia C.
Published: March 2003

Average concentrations of NaCl and KCl (as salt substitute) in a cylindrical Fynbo cheese during salting and ripening stages were analytically modelled for partial and total volumes. The results obtained using the novel analytical solutions were compared with those obtained by numerical modelling solutions considering the computing central processing unit (CPU) time necessary for similar error values for each method. The CPU time was reduced when the analytical solutions were used to obtain concentrations with the same significant figures. The equations obtained could probably be used to study solute diffusion in other similar solid foodstuffs. The advantages of analytical solutions are: a short CPU time is required and these solutions can be used to predict parameters by regression of experimental data more easily.
Use of gamma‐irradiation and sulphur dioxide to improve storability of two Syrian grape cultivars (Vitis vinifera)
Authors: Al‐Bachir
Published: March 2003

The feasibility of using gamma‐irradiation and sulphur dioxide to control post‐harvest diseases and to extend the shelf‐life of table grapes in cold storage (1–2 °C) was studied using two cultivars of grapes local to Syria (Baladi and Helwani). The experiment took 2 years. In the first year the clusters of both cultivars were subjected to one of the following treatments, irradiation with 1.0 kGy of gamma‐rays, sulphur dioxide (3 g of Na2S2O5 per 5‐kg cluster) or a combination of both 1.0 kGy of gamma‐irradiation and sulphur dioxide. In the second year clusters of Baladi cv. were treated with 1.5 kGy of gamma‐radiation, sulphur dioxide, and a combination of 1.5 kGy of gamma‐radiation and sulphur dioxide, whereas clusters of Helwani cv. were treated with 0.5 kGy of gamma‐radiation, sulphur dioxide, and a combination of 0.5 kGy of gamma‐irradiation and sulphur dioxide. Treated and untreated clusters were kept in cold storage. With the exception of Helwani cv. produced in the first year and treated with sulphur dioxide, the results indicated that separate application of sulphur dioxide and gamma‐radiation reduced the rotting induced by Botrytis cinerea. Gamma‐irradiation in combination with sulphur dioxide was the best method of preserving the two varieties of table grapes.
Monitoring thermally induced conformational changes in bovine muscle myosin solutions by competitive indirect enzyme‐linked immunosorbent assay (Ci‐ELISA)
Authors: Lee Ju‐Woon , Park Jong‐Heum , Kim Cheon‐Jei , Shin Heuyn‐Kil
Published: March 2003

Competitive indirect enzyme‐linked immunosorbent assay (Ci‐ELISA), using antibodies against myosin whole molecules (MWMS) and the myosin subfragments, heavy meromyosin S‐1 and light meromyosin (LMM), has been used to monitor the conformational change of bovine myosin on heating. The immune affinity of all antibodies for myosin heated at designated temperatures (37–100 °C) suggested structural changes to myosin in two stages; in the initial stage, 40–55 °C, the immune affinity increased; in the second stage, 55 °C and above, the immune affinity decreased sharply. The immune affinity of anti‐MWM immunoglobulin G (IgG) increased relative to the control (37 °C) in the initial stage, with maxima at 45 and 55 °C. Anti‐S‐1 IgG bound to myosin heated at 40–60 °C better than to the control (P < 0.05), and anti‐LMM IgG demonstrated an increase in immune affinity from 37 °C to 50 °C. There was no significant change in immune affinity above 80 °C. Conformational change in myosin was pH dependent; conformational changes began at lower temperatures with reduced pH. S‐1 was affected more by pH than either MWMs or LMM.
The effect of pre‐treatment on the strength and dehulling properties of pigeonpea grain
Authors: Phirke Prabhakar S. , Bhole Nivrutti G.
Published: March 2003

Summary The effect of different pre‐treatments, i.e. grain scarification, chemical treatment and hot milling, on the strength and dehulling properties of pigeonpea grain was studied by measurement of the forces required for removal of the seed coat from cotyledons and of cotyledons from each other. The dehulling index, dehulling time, product recovery and amount of intact pearled grain were determined after dehulling the pre‐treated grain. The results revealed that a significant (P < 0.05) reduction in seed coat adhesion could be obtained by urea treated scarified grain when hot milled. This, in turn, increased the dehulling index for both the cultivars studied, with subsequent reduction in dehulling time, resulting in a high product recovery of about 81%, and an increased quantity of intact pearled grain of about 39%.
Studies on genetic variants of α‐lactalbumin and β‐lactoglobulin from milk of native Portuguese ovine and caprine breeds
Authors: Pintado Manuela E. , Malcata F. Xavier
Published: March 2003

Summaryα‐Lactalbumin (α‐La) and β‐lactoglobulin (β‐Lg) fractions were obtained from Portuguese native breeds of ewes and goats by preparative gel filtration and further purified by ion exchange; their genetic variants were characterized by isolectric focusing, and β‐Lg isolated was further characterized by differential scanning calorimetry. Separation of β‐Lg and α‐La by molecular exclusion from native whey was relatively easy, whereas β‐Lg from both breeds accounted for a single peak via ion exchange under various gradients of NaCl. Isoelectric focusing has indicated that α‐La from ovine and caprine wheys appears as a single variant in each case, as well as β‐Lg from caprine whey; however, β‐Lg from ovine whey appears as two peaks, tentatively denoted as β‐Lg A and B. Further comparison with bovine whey made it possible to rank whey proteins by increasing value of pI as follows: bovine β‐Lg A, bovine α‐La, bovine β‐Lg B, ovine and caprine α‐La, ovine β‐Lg A, and finally ovine β‐Lg B and caprine β‐Lg. β‐Lg from goat's whey showed the highest onset temperature of denaturation in the presence (78–97 °C) or absence (90–100 °C) of NaCl for every pH tested; when NaCl was present, a good correlation between pI and onset temperature of denaturation was obtained for pH values in the range 3.5–7.0.
Physical characterization of thermally induced networks of lupin protein isolates prepared by isoelectric precipitation and dialysis
Authors: Kiosseoglou Antonios , Doxastakis Georgios , Alevisopoulos Stefan , Kasapis Stefan
Published: March 2003

Summary Protein isolates of Lupinus albus were obtained from full fat and defatted lupin flour using isoelectric precipitation or dialysis. Calorimetric tests demonstrated that the main protein fractions of the isolates denature well below 100 °C. Mechanical spectra of isolate dispersions obtained at 80 °C indicated the formation of a ‘pseudogel’ whose cohesion increased during cooling to 10 °C. Subsequent heating to 90 °C encouraged extensive formation of disulphide bonds as it produced gels that were insoluble in sodium dodecyl sulphate and urea solutions. Dialysis produced isolates of lower gelling concentrations, which also formed networks of a stronger relative elastic character. The presence of NaCl at concentrations up to 0.5 m had a reinforcing effect on networks. Protein over‐aggregation caused the opposite effect at higher salt levels. Finally, a comparison with results in the literature on soybean protein gelation suggested similar denaturation temperatures and a common pattern of structure formation for the two legume proteins.
Expression of recombinant wild‐type and mutant β‐Lactoglobulins in the yeast Pichia pastoris
Authors: Wilson Christine , Quarrie Lynda , Allan Gordon J. , Flint David J. , Sawyer Lindsay , Holt Carl
Published: March 2003

Summary We have produced β‐lactoglobulin gene constructs in the pGAPZαA vector for over expression of recombinant wild‐type and a putative monomeric mutant protein in Pichia pastoris. Levels of expression of at least 150 mg L−1 of the wild‐type were achieved in shake flask culture. Ion exchange chromatography showed that the expressed recombinant wild‐type β‐Lg eluted as a heterogeneous mixture of species, some of which may be owing to small variations in the N‐terminus and some to ligand binding. The putative monomeric β‐lactoglobulin construct gave an expressed protein that was recognized by anti bovine β‐lactoglobulin antibody, but we do not know yet if it forms monomers rather than dimers.
Apparent chemical composition of nine commercial or semi‐commercial whey protein concentrates, isolates and fractions
Authors: Holt Carl , McPhail Deborah , Nevison Ian , Nylander Tommy , Otte Jeanette , Ipsen Richard H. , Bauer Rogert , Ōgendal, Lars , Olieman Kees , de Kruif Kees G. , Léonil Joëlle , Mollé Daniel , Henry Gwénaële , Maubois Jean Louis , Pérez M. Dolores , Puyol Pilar , Calvo Miguel , Bury Stella M. , Kontopidis George , McNae Iain , Sawyer Lindsay , Ragona Laura , Zetta Lucia , Molinari Henriette , Klarenbeek Bert , Jonkman Margrethe J. , Moulin Jacques , Chatterton Dereck
Published: March 2003

Summary Analytical results are given for whey powders prepared on a commercial or semi‐commercial scale by three companies. Altogether, five preparations enriched in β‐lactoglobulin, four whey protein isolates and a fraction enriched in α‐lactalbumin were analyzed for protein composition, including %β‐lactoglobulin, α‐lactalbumin, bovine serum albumin, casein (glyco) macropeptide and the main triglycerides. Protein composition was determined by high pressure gel permeation and reversed phase liquid chromatography and by capillary zone electrophoresis. The extent of modification of the native β‐lactoglobulin structure was also measured through the degree of lactosylation and the fraction of accessible free sulphydryl groups. One significant finding was that the calculated recovery of protein following quantitation of the chromatogram or electropherogram was seldom above 90% and occasionally below 60% of that loaded onto the column or capillary, raising doubts as to the reliability of the analytical results. Extrapolation by linear regression to 100% recovery allowed estimates to be made of the true β‐lactoglobulin composition of the samples. The nine samples could be placed into three distinct groups with estimated true β‐lactoglobulin weight % of 70.9 ± 1.1, 62.0 ± 3.4 and 39.5 ± 4.9. Physico‐chemical properties of the group of samples are reported elsewhere (Holt et al., 1999).
Is the rate of sulfur‐disulfide exchange between the native β‐Lactoglobulin and PDS related to protein conformational stability?
Authors: Owusu Apenten Richard K. , Galani Despina
Published: March 2003

Summary The sulfhydryl (SH) group of β‐lactoglobulin (β‐Lg) affects many of its functional properties. Native β‐Lg was treated with pyridine disulfide (PDS) at pH 2.6–8.5 (25 °C). SH‐disulfide exchange was monitored by spectrophotometry. The kinetics of β‐Lg sulphydryl‐disulphide exchange was compared with the same reaction for reduced glutathione (GSH). From such results we estimate, ΔGex, the free energy change for exposing the SH‐group of β‐Lg to solvent. The numerical value for ΔGex is equal to the free energy change for β‐Lg dissociation at pH 7. At neutral pH, the rate of sulphydryl‐ disulphide exchange appears to be controlled by the dimer‐monomer dissociation equilibrium. At other solvent pHs, β‐Lg sulphydryl reactivity towards a small disulphide compound like PDS may not involve the dissociation of native β‐Lg.
Characterization of industrial processed milk by analysis of heat‐induced changes
Authors: Morales Francisco‐J. , Romero Carmen , Jiménez‐Pérez Salvio
Published: March 2003

Summary Thermal indicators in milk, which had been subjected to one of the six industrial processes of thermization, pasteurization, direct and indirect UHT‐sterilization, pre‐sterilization and in‐bottle sterilization, were studied. The following three indices of heat damage were analyzed by high performance liquid chromatography (HPLC), hydroxymethylfurfural (HMF), lactulose and acid‐soluble β‐lactoglobulin(β‐LG). Average amounts found were 1710 mg/l of β‐LG and 2.49 μmol/l of HMF in pasteurized milk. In UHT milk, the amounts for direct and indirect processes were 389 and 322 mg/l of β‐LG, 12.0 and 250 mg/l of lactulose and 5.6 and 8.7 μmol/l of HMF. In sterilized milk the amounts were 1120 mg/l of lactulose and 22 μmol/l of HMF, without any detectable presence of undenatured whey proteins. On the basis of the time/temperature profiles, a sterilization factor, expressed as seconds, was defined for each thermal treatment. By applying discriminant analysis each industrial process could be classified independently at the 95% confidence level (pasteurization, UHT‐treatment and in‐bottle sterilization), but direct‐UHT treated milk could not be discriminated from indirect‐UHT milk, nor thermized milk from raw bulk milk. The simultaneous application of several heat‐induced parameters improves the classification of industrial processed milks, and is therefore a useful tool for optimization of the processing conditions.
Influence of oxygen concentration and temperature on respiratory characteristics of fresh‐cut green onion
Authors: Hong Seok‐In , Kim Dong‐Man
Published: March 2003

The characteristics of the respiration rates in precut green onion, as influenced by oxygen levels and temperature, were examined to provide design factors for modified atmosphere packaging (MAP). Fresh‐cut green onions (Allium fistulosum L.) were prepared and sealed, with and without a CO2 absorbent, in gas‐tight glass containers that had initially been purged with air or a gas mixture (O2 9%/N2 balance). The containers were stored at different temperatures (0, 10, 20 °C). At 10 °C, the maximum O2 uptake rate (Vm) and the O2 concentration at half‐maximum (Km) uptake rate were 30.95 mL kg−1 h−1 and 1.63%, respectively. Regardless of temperature, the lower O2 limit was estimated to be about 1.0% O2 on the basis of respiratory quotient (RQ) increase. Respiration of cut green onion was dependent on O2 concentration as well as temperature, as shown by applying the Michaelis–Menten type model and the Arrhenius equation. However, the presence of CO2 had little effect on O2 uptake of cut green onion at relatively high O2 concentrations (≤20%).
Flavour retention during high temperature short time extrusion cooking process: a review
Authors: Bhandari Bhesh , D'Arcy Bruce , Young Gordon
Published: March 2003

Research on the stability of flavours during high temperature extrusion cooking is reviewed. The important factors that affect flavour and aroma retention during the process of extrusion are illustrated. A substantial number of flavour volatiles which are incorporated prior to extrusion are normally lost during expansion, this is because of steam distillation. Therefore, a general practice has been to introduce a flavour mix after the extrusion process. This extra operation requires a binding agent (normally oil), and may also result in a non‐uniform distribution of the flavour and low oxidative stability of the flavours exposed on the surface. Therefore, the importance of encapsulated flavours, particularly the β‐cyclodextrin‐flavour complex, is highlighted in this paper.
Ethical dilemmas in sustainable agriculture
Authors: Korthals M.
Published: March 2003

In this article, I argue that agriculture and food production processes are subject to what I refer to as ‘dilemmatic situations’. These dilemmatic situations are rather new, and require a new orientation in ethics to account for them. Ethics has to give up long‐cherished ideals, such as: (a) the identification of ethics with a set of obligations that require people to do certain actions; (b) the idea that there is only one good solution to an ethical problem; (c) the idea that compromises are only second best solutions; and finally (d) the dogma that solutions to ethical problems should exclude considerations of technology. Instead, I maintain that ethics must be more flexible. In the case of dilemmas facing agriculture, this means that ethics must respect consumer decisions in a substantial sense: indeed, we must look for ways to enhance the influence of consumers on the food chain and to help consumers to make up their minds with respect to new developments. Ethics must also reorient itself toward technology as a producer of values, and embrace pluralism in agriculture and food. Finally, ethics must look for compromises in such cases as the dilemmatic situation of agricultural sustainability vs. animal well being.
Alleviation of the adverse effect of cooking on sorghum protein digestibility through fermentation in traditional African porridges
Authors: Taylor Janet , Taylor John R. N.
Published: March 2003

Cooking sorghum is well known to reduce its protein digestibility. In southern Africa fermented sorghum porridges are commonly consumed. Knowledge is lacking as to how their preparation affects sorghum protein digestibility. Five sorghum varieties of varied origin were fermented using traditional semi‐solid state fermentation. In vitro protein digestibility and a new index, in vitro insoluble protein digestibility, were measured. Both increased during fermentation, generally within the first day, coinciding with a strong decrease in pH. The increase in insoluble protein digestibility suggests fermentation causes structural changes in the sorghum storage proteins (prolamins and glutelins), making them more accessible to pepsin attack. Wet cooking during porridge‐making greatly reduced protein digestibility. Combining fermentation with cooking, either fermenting then cooking or cooking then fermenting, significantly improved protein digestibility over wet cooking alone. Thus natural fermentation, as applied in traditional African porridge preparation is an effective method of improving the protein digestibility of cooked sorghum.
Moisture adsorption by milk whey protein films
Authors: Yoshida C. M. P. , Antunes A. C. B. , Antunes A. J.
Published: March 2003

Edible films, using whey protein as the structural matrix, were tested for water vapour diffusion properties. Whey protein films were prepared by dispersing 6.5% whey protein concentrate (WPC) in distilled water with pH kept at 7.0. Glycerol was the plasticizer agent. Film slabs (13.5 × 3.5 cm) were put in a chamber at 25 °C and 75% relative humidity, being held in vertical planes for different periods of time. The mass gain was determined throughout the experiment. We show that moisture adsorption by milk whey protein films is well described by a linear diffusion equation model. After an adsorption experiment was performed the solution of the diffusion equation was fitted to the data to determine the diffusion coefficient of the material.
The influence of fungal α‐amylase supplementation on amylolytic activity and baking quality of flour
Authors: Ćurić Duška , Ðugum Jelena , Bauman Ingrid
Published: March 2003

In order to determine the quantity of fungal α‐amylase to be added to flour of low amylolytic activity, it was thought necessary to develop a method suitable for measuring the activity of both cereal and fungal α‐amylase. For determination of fungal α‐amylase activity, thermolability of the enzyme made the classical Falling Number Method not suitable. The Fungal Falling Number (FFN) Method was developed to measure amylolytic activity in flour supplemented with fungal α‐amylase. Reproducibility of Fungal Falling Number measurements on tested flour samples is high (standard deviation was 16.33 s and the variation coefficient 6.19%). The ratio between flour amylolytic activity, after addition of fungal α‐amylase, and the quantity of the added fungal α‐amylase, as well as the initial amylolytic activity of flour was described by the multiple regression non‐linear model. By applying the model, one could account for 88.48% of total deviations of the regression of the measured Fungal Falling Number values, making the model representative. Such a model can be used to determine the required quantity of fungal α‐amylase to achieve the optimal amylolytic activity of flour for the baking industry, provided the starting amylolytic activity in flour is known. The analysis of test baking results has shown that flour with an amylolytic activity range of 100 s <FFNf < 200 s yields bread loaves of the largest volume and excellent sensory properties.
Molecular and catalytic properties of phytate‐degrading enzymes (phytases)
Authors: Konietzny Ursula , Greiner Ralf
Published: March 2003

Phytate‐degrading enzymes catalyse the step‐wise release of phosphate from phytate, the principle storage form of phosphorus in plant seeds and pollen. They are widespread in nature, occurring in plants and micro‐organisms, as well as in some animal tissues. Phytate‐degrading enzymes have been studied intensively in recent years because of the great interest in such enzymes for reducing phytate content in animal feed and food for human consumption. Phytate‐degrading enzymes are also of interest for producing defined breakdown products of phytate for kinetic and physiological studies. Certain myo‐inositol phosphates have been proposed to have novel metabolic effects and therefore, the physiological role of different myo‐inositol phosphates is presently undergoing extensive research. Generally, phytase behaves like a monomeric enzyme with molecular masses between 40 and 70 kDa. Up to now, two main types of phytate‐degrading enzymes have been identified; acid phytate‐degrading enzymes with an pH optimum around pH 5 and alkaline phytate‐degrading enzymes with an pH optimum around pH 8. Most of the so far described phytate‐degrading enzymes belong to the acidic type, and their optimal pH ranges from 4.5 to 6.0. This review summarises the molecular features as well as catalytic properties of phytate‐degrading enzymes and also discusses enzymatic phytate degradation.
In vitro properties of phytases from various microbial origins
Authors: Simon Ortwin , Igbasan Francis
Published: March 2003

Summary For the evaluation of the effectiveness of phytase preparations as feed additive, in vitro properties like temperature optimum, temperature stability, pH optimum and pH profile or proteolytic stability are of utmost importance. Although at present all commercial phytase preparations authorized as feed additives in the EU are produced by recombinant filamentous fungi and have similar in vitro properties (acidic pH optimum, narrow pH range, low thermostability) the diversity of microbial phytases is great. Microbial sources for phytases span from fungi and yeasts to bacteria. Some of the naturally occurring phytases were identified to have high thermostability and a broad pH range (e.g. Aspergillus fumigatus phytase). The bacterial Bacillus phytases generally differ from other phytases, having a pH optimum from 7.0 to 8.0, being Ca2+ dependent and highly specific for phytate. Thermostability can considerably be increased by protein engineering. A so‐called Consensus phytase encoded by a synthetic gene was found to be stable in aqueous solutions at 70 °C and in feed at pelleting temperatures of 80–90 °C. The rate and site of inactivation of feed enzymes in the digestive tract are determined by their susceptibility to proteolytic enzymes. Highest residual activities after incubation in the presence of pepsin or in supernatants of stomach digesta was observed for Escherichia coli and Consensus phytases, while the Bacillus phytase was found to be most resistant to pancreatin. Comparative studies on in vitro properties of enzymes intended for use as feed additives provide valuable information for prediction of in vivo effectiveness.
Quality changes in frozen and thawed, cooked puréed vegetables containing hydrocolloids, gums and dairy powders
Authors: Downey Gerard
Published: March 2003

Summary Freezing and thawing have been shown to adversely affect the centrifugal drip loss and maximum resistance to penetration of cooked, puréed vegetables (potatoes, carrots and turnips). Amelioration of these effects has been investigated through the addition of cryoprotectants (xanthan gum, guar gum, pectin, carrageenan, sodium caseinate, whey protein concentrate). The effect of each cryoprotectant varied with vegetable type. In general, gums (xanthan and guar) proved most effective in reducing drip losses although carrageenan and pectin exhibited some ability in this regard. Dairy powders produced no effect on drip loss but did alter maximum resistance values after thawing. Depending on the vegetable, quality maintenance or improvement after thawing may be achieved through selection of an appropriate cryoprotectant.
Development of methodology for assessing the heating performance of domestic microwave ovens
Authors: James C. , Swain M. V. , James S. J. , Swain M. J.
Published: March 2003

Summary There is a need for standard methods of testing domestic microwave ovens that relate to their reheating performance with chilled convenience meals. The investigations reported here have produced a simple procedure for comparing the three most important reheating characteristics of a domestic microwave oven: its ‘true’ power; heating variability; and repeatability. The tests are relatively simple to do, and require only a few additional items of equipment to those that a laboratory performing existing output power tests would already possess. Three identical tests are required: one with a liquid test material, one with a solid and one with a combination of the two components. One additional stage is done with the liquid test material. The data produced can be reduced to three numbers, which are measures of the true power, variability and repeatability of the oven. A further simple analysis, which weights the relative importance of each factor to the consumer, would produce a single value for the oven's relative reheating performance. Ovens with unusual or extreme performance characteristics can therefore be identified easily.