bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of experiments for improving the precision in the estimation of diffusion parameters under isothermal and non‐isothermal conditions
Authors: Brandão Teresa R. S. , Oliveira Fernanda A. R. , Cunha Luís M.
Published: March 2003

Mass transfer in food processing can often be described by Fick’s second law, with diffusivity increasing with temperature according to an Arrhenius‐type relationship. For predictive purposes it is most important to determine with high precision and accuracy these model parameters: the diffusivity at a given temperature, the activation energy and the pre‐exponential factor for a range of temperatures. The main objective of this work was to define optimal experimental conditions for a process controlled by internal diffusion, on the basis of the concept ofD‐optimal design, both for isothermal and non‐isothermal conditions. It was concluded that, for a spherical geometry and at a given temperature, experiments should consist of a number of replicates taken at the time required to reach a fractional loss/uptake of solute of 0.716. Two experiments should be conducted, one at each of the extreme temperatures of the range tested. Under non‐isothermal conditions the optimal design is more complex, as it also depends on the heating rate. It was further concluded that, although the definition of the experimental design requires preliminary estimates of the parameters, deviations between the ‘guessed’ and the ‘true’ values do not seriously compromise the results.
Perspectives on the 21st century development of functional foods: bridging Chinese medicated diet and functional foods
Authors: Xu Yue
Published: March 2003

Functional foods, also known as nutraceuticals, medical foods or nutritional foods, are driving food markets around the world and are expected to be one of the emerging trends for the food industry in the new millennium. The concept of functional foods is rooted in a tradition, particularly in Asia, where people have always believed that a balanced diet and some herbal foods are therapeutic. However, while extensive studies in biochemistry and immunology, as well as clinical trials, have been conducted on selected functional foods or ingredients, the scientific features of most traditional herbals remain almost unknown. However, the fastest growing food market in the United States is that of herbal‐based nutraceuticals such as ginseng, garlic and medical mushrooms. This review describes different aspects of functional foods and the Chinese medicated diet on the basis of current knowledge, discusses the building blocks for the science of functional foods and proposes a possible way to fuse a Chinese medicated diet into functional foods.
Re‐examination of the interactions between starch and salts of metals from the non‐transition groups
Authors: Lai Vivian M.‐F. , Tomasik Piotr , Yen Ming‐Tsung , Hung Wei‐Ling , Lii Cheng‐yi
Published: March 2003

The interactions between potato starch and the salts of alkali–earth metals and lead were examined by using scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), differential scanning calorimetry (DSC), 17O and 35Cl NMR. For the starch blended with saturated solutions of the salts, gel‐like, shear‐thinning or semi‐solid appearances were observed in relation to the ion property of the salts. The volume of saturated salt solutions required for producing shear‐thinning properties correlated significantly with the property of anions. SEM and EDS studies on the starches after soaking in 0.5 M salt solutions suggest that both divalent cations and accompanying anions of the salts penetrated into the granule during soaking treatments. Also, the cations (especially Mg2+ and Pb2+) and anions both displayed some influence on the onset (To) and peak (Tp) temperatures as well as the enthalpy change (ΔH) during thermolysis of the starches. From these results and NMR data, the major ion species (anions or cations) interacting directly with starch could be elucidated partially with respect to the salt variety and concentration and preparation condition. The roles of free water content and water structure in the physical characteristics of the starch systems examined were negligible.
Solubilization of onion with polysaccharide‐degrading enzymes
Authors: Suh Hyung Joo , Noh Dong Ouk , Choi Yang Moon
Published: March 2003

For the selection of suitable enzymes for the solubilization of onion, degree of solubilization (DS) values were measured. The DS values of Pectinex and Viscozyme were 75.8 and 78.4%, respectively, which indicates they have higher specific activities than Cereflo and Celluclast. The enzyme mixture of Pectinex and Viscozyme (relative ratio of 1:3) had higher DS values and reducing sugar content than Pectinex alone. The enzyme mixture degraded onions with a synergistic effect, solubilizing 85% of the onion. The DS values and reducing sugar content at the optimal condition (pH 4.5 and 45 °C) reached a maximum of 85% and 494.8 mg g–1 of onion, respectively. The DS values and reducing sugar content increased with increasing reaction time, reaching a maximum of 89% and 517.5 mg g–1 of onion, respectively. When cooking pork, onion appeared to be preferable to onion hydrolysate, however there was no significant difference. The sweetness and preference of pork cooked with 3% addition of hydrolysate per gram of pork meat were the highest but those were not different significantly from those cooked with less than 10% addition of hydrolysate per pork meat.
A comparison of various rheological properties for modelling the kinetics of thermal softening of potato tissue (c.v. Monalisa) by water cooking and pressure steaming
Authors: Alvarez María Dolores , Canet Wenceslao
Published: March 2003

The kinetics which can be used to describe thermal softening of potato tissue by water cooking and pressure steaming were established and the temperature dependence of rheological and textural properties, using six different instrumental objective methods as firmness indicators, was determined within the temperature range of 100–122 °C. In water cooking at 100 °C and in steaming at 100, 112 and 117 °C, the thermal softening was best expressed by one simple pseudo first‐order kinetic mechanism, which was considered to be the response to the changes in the pectic material in the cell wall and interlamellar region. Tension energy was the best rheological property for establishing the kinetics of softening of potato by water cooking, whereas maximum shear force was the best method of representing the tissue softening by steaming, using first‐order models. Steaming at 122 °C caused overcooking of the tissue, even for short times. At this high temperature, rheological parameters (compression, tension and creep compliance) and textural properties from Texture Profile Analysis (TPA) fitted second‐order models. When second‐order models were used, the Arrhenius equation was significant for chewiness, indicating that this textural property can be useful for detecting overcooking caused by prolonged pressure steaming in the experimental temperature range.
Sensory quality of marinated frozen stored chicken thighs as affected by dietary fish fat and vitamin E
Authors: Mielnik Maria B. , Herstad Olav , Lea Per , Nordal John , Nilsson Astrid
Published: March 2003

The effects of diets containing fish meal (0 or 4%), fish silage (0 or 4%) and vitamin E (60 or 200 mg kg–1) and the processing effect of marinating with sodium citrate (0.24 or 0.48%) or ascorbate (0.31 or 0.62%) have been studied to test the hypothesis that oxidative stability of frozen stored chicken thighs can be improved by such treatments. A trained sensory panel assessed the samples after storage at –25 °C for 1 week, 3 and 6 months. Feed with 4% fish meal resulted in increased fish flavour and odour of the thighs while 4% fish silage had a smaller effect on these attributes. Fish meal and fish silage added together into the feed by an amount of 4% each, caused strong fish flavour and odour in the product and accelerated the rancidity process. High concentration of vitamin E (200 mg kg–1) in the feed reduced rancidity when 4% fish products had been added to the feed, but no effect was noted when 4% fish meal plus 4% fish silage had been added together. High concentration of ascorbate in the brine (0.62%) decreased sensory score for rancidity attributes (hay, grass, soap and paint), while high concentration of citrate (0.48%) increased these parameters in frozen stored chicken thighs.
A protein which masks galactose receptor mediated phage susceptibility in Lactococcus lactis subsp. lactis MPL56
Authors: Tuncer Yasin , Akçelik Mustafa
Published: March 2003

A 28.5‐kb plasmid, isolated from Lactococcus lactis subsp. lactis MPL56, causes complete inhibition of four lactococcal phages. Cell wall characteristics of wild‐type strain MPL56 were compared with its 28.5 kb plasmid‐cured, phage‐sensitive derivative MPL56‐22. After proteolytic enzyme treatments, adsorption of phages occurred at high levels, an example is 94.6–98.5% in MPL56 cells. Analysis of cell wall extracts of MPL56‐22 by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) indicated that the only difference between strains was the 55.4 kDa band in protein patterns of MPL56. Adsorption of the four phages was completely inhibited when MPL56‐22 cells were subjected to SDS, Triton‐X‐100, HCl and NaOH treatments. Lectins that were specific for glucose/mannose and N‐acetylglucosamine did not prevent adsorption of phages in cell wall extracts of MPL 56‐22. However a lectin specific for galactose (MCA; Momordica charantia) completely inhibited adsorption of these phages in cell wall extracts of MPL56‐22. HPLC patterns of cell wall carbohydrates of MPL56‐22 and its HCl treated preparations showed that the most prevalent difference was the galactose on untreated MPL56‐22 cell wall chromatograms.
Anti‐oxidant activity and mechanism of action of trans‐resveratrol in different lipid systems
Authors: Marinova Emma M. , Yanishlieva Nedyalka V. , Totseva Iskra R.
Published: March 2003

The anti‐oxidative properties of trans‐resveratrol were studied in the concentration range 0.02–0.20% (8.8 × 10−4–8.8 × 10−3 M) during autoxidation of pure triacylglycerols of lard (TGL) and of pure triacylglycerols of sunflower oil (TGSO), as well as of commercial sunflower oil at 100 °C. In sunflower oil trans‐resveratrol showed no anti‐oxidative activity. In pure lipid systems trans‐resveratrol considerably retarded the oxidation process, the effect being stronger in the less oxidizable substrate (TGL). The effectiveness (stabilization factor F), strength (oxidation rate ratio, ORR) and activity (A=F/ORR) of the different anti‐oxidant concentrations were determined. The activity A was found to increase dose dependency as follows: A=3750–15425 for TGL, A=79–207 for TGSO. The participation of trans‐resveratrol in the side reactions of inhibited oxidation was discussed.
Involvement of pectolytic micro‐organisms in coffee fermentation
Authors: Avallone Sylvie , Brillouet Jean M. , Guyot Bernard , Olguin Eugenia , Guiraud Joseph P.
Published: March 2003

During the fermentation of Coffea arabica L., the most frequently found pectolytic bacteria were Erwinia herbicola and Klebsiella pneumoniae. These micro‐organisms produce pectatelyase which is unable to depolymerize esterified pectins of mucilage without previous de‐esterification. Furthermore, the optimal activities are observed at pH 8.5 whereas fermentation conditions are acidic (5.3–3.5). The major lactic acid bacteria, Leuconostoc mesenteroides, do not produce pectolytic enzymes. Only a Lactobacillus brevis strain, rarely isolated with a low frequency, shows a polygalacturonase activity compatible with fermentation conditions. Mucilage decomposition seems to be correlated to acidification and not to enzymatic pectolysis. Inoculation with pectolytic micro‐organisms allows microbiological control of the fermentation but does not speed up the process. It would be preferable to use lactic acid bacteria so that the pH remained as close as possible to natural fermentation, where acidification is important. This practice would standardize the coffee fermentation microflora and therefore control the end product quality.
Absorption kinetics of oxygen scavengers
Authors: Tewari Gaurav , Jayas Digvir S. , Jeremiah Lester E. , Holley Richard A.
Published: March 2003

The oxygen (O2) absorption kinetics of six commercial O2 scavengers were studied. The scavengers were placed in bags which were filled with 240 mL of air, 4.5 L N2 + 15 mL of air, or 3.5 L CO2 + 9 mL of air. The O2 concentration in each bag was measured at hourly intervals for 8 h. The effects of variability among individual scavengers, initial O2 concentrations of 20% or 500 ppm (0.05%), temperatures of 25, 12, 2 or −1.5 °C, and scavenger capacity on the O2 absorption rate were determined. In addition, the effect of placing scavengers within over‐wrapped trays within bags, was examined. Rates of O2 absorption varied by factors of up to 2 between individual O2 scavengers of the same type, but rates of absorption by groups of four scavengers of the same type were similar. Low temperatures gave longer O2 half‐life when compared with those at higher temperatures, e.g. O2 half‐lives of 7.1 and 1.0 h at −1.5 and 25 °C, respectively, were obtained for one scavenger type. Shorter O2 half‐lives were obtained in air than in N2 atmospheres at the same temperature, e.g. O2 half‐lives of 1.0 and 3.3 h in air and N2 at 25 °C, respectively, were obtained for one scavenger type. The O2 absorption reactions were of first order for both high and low initial O2 concentrations. However, O2 concentration was the primary limiting factor for O2 absorption in atmospheres having O2 concentration of 500 ppm because of the dominance of diffusion. Scavengers, when placed within over‐wrapped trays within bags had up to 12 times longer O2 half‐lives, indicating that the O2 permeable film acts as an O2 barrier when pack atmosphere has low O2 concentrations. To obtain consistent and reproducible results, it is recommended that multiple scavengers be used in a packaging system. The appropriate number should be based on scavenger type, desired O2 absorption rate, storage temperature, and pack atmosphere (air/N2/CO2).
A review of the feasibility of producing processed cheese using non‐enzymatic direct acidification procedures
Authors: Pal M. Ashraf
Published: March 2003

This review covers various aspects of studies, which were done to develop processes to make products that resemble traditional/processed cheese without the use of micro‐organisms or enzyme system. Several manufacturing techniques and incorporation of various ingredients/additives, examples of which are emulsifying salts, texture modifiers and flavour enhancers, in the formulations are discussed. Characteristics like rheology, chemical composition, biochemical changes and microstructure of such products are also given.
Swelling and contraction driven mass transfer processes during osmotic dehydration of uncharged hydrogels
Authors: Eichler Sigal , Ramon Ory , Cohen Yachin , Mizrahi Shimon
Published: March 2003

The processes of swelling or contraction act as driving forces and thus play important roles in mass transfer during osmotic dehydration of a hydrophilic gel, such as polyacrylamide (PAAm). These driving forces seem to be determined by the interaction between the low molecular solute and the gel polymeric matrix. In a solution of sugars or sodium chloride, the gel undergoes an initial rapid mass loss until it reaches a turning point where the mass transfer process is reversed and the gel swells to a significantly larger extent than in water. However, in solutions of relatively high concentration of sodium citrate or sodium acetate, the gel undergoes only a contraction process and is incapable of regaining any of its lost mass. Empirically, the swelling process follows first order kinetics, which seems to become slower the larger the solution viscosity.
Rheological behaviour of blueberry cloudy juice (Vaccinium corymbosum L.)
Authors: Cepeda E. , Hermosa M. , Llorens F. , Villarán M. C.
Published: March 2003

The rheological behaviour of blueberry cloudy juice (Vaccinium corymbosum L.), prepared from fresh berries, was studied as a function of solids concentration, in the range 25–61 °Brix, at different temperatures (5–50 °C), with a control rate (CR) rheometer. Cloudy juice was concentrated by vacuum evaporation, and solutions at other concentrations were prepared from the concentrate by adding the liquid collected as distillate. The juices were slightly thixotropic between 45 and 61°Brix. For lower concentrations, the thixotropy was low and could be easily eliminated by shearing. The power law model was applied to fit the pseudoplastic behaviour. The activation energy for flow, evaluated with the Arrhenius–Guzman equation, increased with solids concentration and ranged from 4.6 to 24 kJ gmol–1. A non‐linear correlation, accounting for temperature and concentration effects on the consistency coefficient, was identified.
Collagen of octopus Callistoctopus arakawai arm
Authors: Nagai Takeshi , Nagamori Keiko , Yamashita Eiji , Suzuki Nobutaka
Published: March 2003

In an investigation into making more effective use of underutilized fisheries resources, collagen was prepared from Callistoctopus arakawai arm. The arm was only slightly solubilized in acetic acid but on digestion with 10% pepsin (w/v), pepsin‐solubilized collagen (PSC) was successfully produced. The PSC obtained was a pinkish fibre. The yields of acid‐solubilized collagen (ASC) and PSC were about 10.4 and 62.9%, respectively. The PSC has a chain composition of α1α2α3 heterotrimer, different from Octopus vulgaris skin. The denaturation temperature of this collagen was lower than porcine collagen. This report indicates that C. arakawai has potential for supplementing the skin of land vertebrates as a source of collagen.
Rheology of spray‐dried egg yolk‐stabilized emulsions
Authors: Moros José E. , Franco José M. , Gallegos Críspulo
Published: March 2003

This paper deals with the influences that concentrations of oil fraction (65–77.5% w/w) and egg yolk (1–5% w/w), as well as temperature (5–35 °C), exerted on the droplet size distribution and rheological functions of concentrated oil‐in‐water food emulsions that were stabilized by a spray‐dried egg yolk product. This work must be considered as a preliminary study concerning the use of low‐in‐cholesterol egg yolk as emulsifier. In order to achieve this aim, steady‐state flow and dynamic viscoelasticity tests were done with emulsions processed with a rotor‐stator turbine. The same processing conditions were always maintained. All of the emulsions prepared showed a high stability. An increase in oil fraction yielded higher values for the rheological functions, and larger droplet diameters. The influence of processed egg yolk concentration was more complex. Thus, an increase in egg yolk content yielded lower values for the rheological functions, but, after a particular concentration, a further increase in emulsifier content yielded higher values for the rheological functions. The experimental results have been discussed taking into account the close relationship between rheology and emulsion structural parameters.
Comparison of physico‐chemical properties of biscuits supplemented with soy and kinema flours
Authors: Shrestha Ashok K. , Noomhorm Athapol
Published: March 2003

Kinema was prepared by natural fermentation of soybeans. Bacillus strains, only tentatively identified, were isolated from the traditional product and used for making kinema in the laboratory. Kinema prepared by both methods was dried and ground to fine flour. Full‐fat and low‐fat soyflours were also prepared. Chemical analysis showed little change in protein and total fat content during fermentation, whereas free fatty acids increased substantially. Crude fibre and total sugar contents were reduced with a simultaneous increase in reducing sugars. Soy and kinema flours were incorporated at the 15% level into biscuit formulation. Protein content of all products was more than 17%. There was little difference in the proximate composition of the four types of biscuits prepared except for biscuits supplemented with low‐fat soyflour. Incorporation of kinema provided red and yellow colour to the corresponding biscuits. Kinema supplementation resulted in decreased hardness but increased weight and spread ratio in fortified biscuits. Evaluation of sensory characteristics showed greater acceptance of kinema‐supplemented biscuits in comparison with full‐fat soyflour‐supplemented biscuits.
A constant humidity air supply system for pilot scale applications
Authors: O'Donnell Aaron M. , Bronlund John E. , Brooks Greg F. , Paterson A. (Tony) H. J.
Published: March 2003

This paper outlines the development of an apparatus to supply air with both controlled temperature and relative humidity, at a variety of flow rates up to 114 L min−1. To achieve adjustable constant relative humidities in the air, the two‐pressure principle was used. This method involved saturating the air at a higher pressure, and then passing the air through a pressure release valve to the lower working pressure to achieve the desired humidity, while controlling the temperature to the desired level. The absolute pressure when the saturation is achieved determines the humidity of the final air. Standard design procedures were followed to ensure the air approached saturation in the pressurized column and that the amount of water was sufficient to make sure the columns would not run out of water during an experiment. The problems encountered included a pressure fluctuation coming from the compressor through the pressure regulator, and a regular fluctuation in the temperature of the water, within a 90 min period, when the water temperature was used to control the air temperature exiting the column. These problems were overcome by using two‐pressure regulators on the air supply and by controlling the temperature of the water rather than the air temperature. The result was a stable but adjustable temperature and relative humidity air supply.
Effects of water, oil, starch, calcium carbonate and titanium dioxide on the colour and texture of threadfin and hairtail surimi gels
Authors: Hsu Cheng‐Kuang , Chiang Been‐Huang
Published: March 2003

The effects of moisture, oil, starch, calcium carbonate and titanium dioxide on the colour and texture properties of surimi gels were studied. Increasing the moisture or oil contents raised the L* values but reduced the b* values. Calcium carbonate and titanium dioxide increased the L* values, while potato starch decreased the b* values. The addition of oil up to the 8% level affected textural properties, but increasing the oil content while maintaining final moisture content constant could significantly decrease the hardness of surimi gels.
Viscoelasticity of oxidized starch/low methoxy pectin mixtures in the presence of glucose syrup
Authors: Kasapis Stefan
Published: March 2003

The structural properties of mixtures of pectin, oxidized starch and glucose syrup were investigated using small deformation dynamic oscillation. In the absence of added calcium, preparations of low methoxy pectin with glucose syrup formed viscous solutions, which remained crystal‐free at subzero temperatures. Samples of oxidized starch and glucose syrup, on the other hand, exhibited solid‐like behaviour because of the crystalline nature of the amylose‐like helices. Mixtures of the two polysaccharides with the co‐solute clearly showed phase inversion from liquid to solid‐like behaviour with increasing amounts of starch in the formulation. The transformation was reflected in the textural properties of samples, which varied from thick solutions to firm gels. The viscoelasticity of the system was modified further by the introduction of high methoxy pectin. Preparations of high methoxy pectin and glucose syrup formed rubbery gels whose amorphous nature underwent a glass transition during cooling.
The effect of aqueous extracted wheat bran on the baking quality of biscuit
Authors: Haque Md. Anwarul , Shams‐Ud‐Din Md. , Haque Anwarul
Published: March 2003

A commercial sample of wheat bran was extracted by a non‐alkaline aqueous extraction process. The extracted residue was dried in a cabinet drier. Biscuits were prepared with extracted or unextracted bran at 2, 4, 6, 8, 10, 12, 16 and 20% substitution levels of flour and evaluated for various quality parameters. Ground bran samples from extracted and unextracted fractions were included for comparison. A control biscuit with no substitution was also included. A critical flour replacement level of 6% by wheat bran produced biscuits close to the control in all the parameters studied. The following sensory properties were evaluated on the biscuit having a 6% replacement level; colour, flavour, texture and overall acceptability, by a panel of nineteen judges. The novelty of the aqueous extracted wheat bran is that it yields better quality biscuits, thus providing a viable alternative to alkaline extraction.
Effect of thermal processing on the texture of canned apricots
Authors: Mallidis Constantin G. , Katsaboxakis Constantin
Published: March 2003

The effect of thermal processing on the texture of canned apricots was studied by using the main cultivar canned in Greece, Bebecou. The test temperature ranged from 82 to 95 °C. The loss of hardness was tested immediately after processing and after 3 months storage. The z‐value was 16.7 °C and the energy of activation 116.5 kJ mol−1. Some restoration in the hardness was found after 3 months storage, which might be attributable to the absorption of sucrose by the fruit.
Influence of whey protein concentrate on the functionality of egg white and bovine serum albumin
Authors: Aryana K. J. , Haque Z. Z. , Gerard P. D.
Published: March 2003

The objective was to elucidate the functionality of various combinations of egg white (EW), whey protein concentrate (WPC) and bovine serum albumin (BSA) and compare the microstructures of their gels. Dispersions of individual proteins (1%, w/v, in imidazole‐HCl pH 7.0) were prepared. The BSA, EW and WPC and were combined in the ratios of 0 : 0 : 1, 1 : 0 : 0, 0 : 1 : 0, 0.5 : 0 : 0.5, 0 : 0.5 : 0.5, 0.5 : 0.5 : 0, 0.33 : 0.33 : 0.33, 0.42 : 0.16 : 0.42, 0.16 : 0.42 : 0.42 and 0.42 : 0.42 : 0.16. The functionalities studied were oil holding capacity (OHC), water holding capacity (WHC), thermostability (TS), foam activity (FA), foam stability (FS), foam density (FD), emulsion stability (ES) and emulsifying activity index (EAI). Gels with a protein concentration of 10% (w/v) in 0.1 M NaCl at pH 7 were used for determination of stress, strain values and microstructural analyses. The R2 was in excess of 0.95 for all attributes studied except FD which had an R2 of 0.85. The results indicate that WPC apparently impacted water entrapment in an additive manner proportional to its concentration. The combination of WPC with EW or BSA resulted in a synergistic effect for TS and FS and an additive effect for OHC, WHC, FD, EAI, gel stress and strain. On the contrary, an antagonistic effect was observed for FA. If a multifunctional combination was to be picked, it would be a 1 : 1 ratio of WPC and BSA as it had the highest number of attributes with synergistic effects. Data indicated there were multifunctional advantage of using WPC.
Microbiological, physicochemical and organoleptic changes in dry‐salted olives of Thassos variety stored under different modified atmospheres at 4 and 20 °C
Authors: Panagou E. Z. , Tassou C. C. , Katsaboxakis K. Z.
Published: March 2003

Microbiological, physico‐chemical and organoleptic changes were studied in dry‐salted olives, cv. Thassos, stored under different atmospheres (100% carbon dioxide and nitrogen, 40% CO2/30%O2/30%N2 and air) at 4 and 20 °C for 180 days. The initial microbial flora comprised of yeasts, no lactic acid bacteria, enterobacteria, pseudomonads or Staphylococcus aureus were detected, as the low water activity/high salt content does not favour their growth. At 4 °C, the population of yeasts declined steadily throughout storage but to a different extent depending on the gaseous atmospheres. At 20 °C, there was an initial decline in yeast counts in all samples followed by a steady increase until the end of the storage period. The CO2 atmosphere was most effective at keeping the number of yeasts low at both storage temperatures. All gas atmospheres prevented fungal growth at both temperatures apart from the samples stored in air. The pH, aw and salt content of the olives did not change significantly throughout the storage period. The prevailing yeast species was the salt tolerant Candida famata. The organoleptic characteristics did not differ significantly among differently treated olives. However, increased rancidity and reduced fruit colour was observed in the samples stored at 20 °C.
Microwave and convective dehydration of ethanol treated and frozen apple – physical properties and drying kinetics
Authors: Funebo Tomas , Ahrné Lília , Prothon Frédéric , Kidman Siw , Langton Maud , Skjöldebrand Christina
Published: March 2003

The objective of this study was to examine how the drying kinetics and physical properties of apples are affected by pre‐treatment with 95% ethanol or freezing at –18 °C before microwave‐assisted air dehydration at 50, 60 and 70 °C. Microwave heating was used to obtain these temperatures in the centre of the apple cubes. After dehydration the shrinkage and rehydration capacity were measured. The texture of dehydrated and rehydrated samples was analysed with a puncture test in a texture analyser. Samples were also analysed with confocal laser scanning microscopy to determine the correlation between physical and microstructural properties. Diffusivity in the different dehydration processes was calculated. Ethanol‐treated apples showed both high rehydration and high effective rehydration capacity compared with the other samples. Freezing before dehydration increased the diffusivity and reduced the firmness of rehydrated apples compared with no pre‐treatment.
Wheat washing with ozonated water: effects on selected flour properties
Authors: Ibanoglu Senol
Published: March 2003

Soft and hard wheat samples were washed using ozonated water (1.5 mg L−1). Milling (rate of extraction), rheological (farinograph and extensograph characteristics), chemical (protein, falling number, sedimentation volume), colour (Hunter Laboratory values) and microbiological (total bacterial and yeast/moulds) properties of flours milled from the washed wheat were evaluated. Results indicated that washing with ozonated water did not significantly alter the chemical, physical or rheological properties of the flours from hard wheat samples. However, small but statistically significant (P=0.05) differences were observed on extensograph values of flours milled from the soft wheat washed with ozonated water. A significant reduction (P=0.05) in the total bacterial and yeast/mould counts was obtained after washing with ozonated water for both soft and hard wheat samples. Results suggest that ozonated water can be successfully used to wash hard wheat without affecting flour quality.
The influence of enzymatic treatment of mash on the analytical composition of apple juice
Authors: Will Frank , Schulz Knud , Ludwig Michael , Otto Konrad , Dietrich Helmut
Published: March 2003

Five apple juices were produced on a pilot scale by crushing the fruit, treating the mash with pectolytic enzymes, pressing, extracting water from the pomace, pasteurization, treatment of the juice with enzymes, combined gelatin/silica sol fining and final ultrafiltration. The temperature of the mash treatment was either ambient or one of 30, 40, 50 or 60 °C, in order to test whether this led to different compositional changes in the corresponding juices. The main emphasis was put on detection of D‐galacturonic acid as the indicator substance for the extent of the enzymatic treatment. In the pasteurized raw juices after pressing we found values from 226 to 398 mg L−1. A distinct increase of the galacturonic acid levels could be observed during the clarification steps. Enzymatic juice treatment raised the concentrations to 580–720 mg L−1. After ultrafiltration, final values of 790–1100 mg L−1 were measured. Generally, the highest values were found in the 50 °C sample, which is the optimum temperature for pectinase activity. This was also true for the colloid concentrations and polyphenols. The influence of the temperature of the enzymatic mash treatment on other characteristic juice parameters like total titratable acidity, density, sugar, and minerals concentrations was low.
Acceptability and nutritive value of keropok‐like snack containing meat offal
Authors: Subba Dilip
Published: March 2003

A simple type of snack was developed from a mixture of wheat flour, cassava flour and pulverized meat offal. Wheat flour, cassava flour and dehydrated bovine lung, liver, spleen and bone were mixed with water to form a dough. The dough was steamed, cut into thin slices and dried. The snack, which is fried before consumption, contains 4.3% protein, 150 mg lysine per 100 g protein, 5 mg per 100 g iron, 51.5 mg per 100 g calcium and 20 μg per 100 g vitamin A.
The morphology and characterization of starch from Pueraria lobata (Willd.) Ohwi
Authors: Du Xian‐Feng , Xu Shi‐Ying , Wang Zhang
Published: March 2003

Pueraria lobata (Willd.) Ohwi starch and its components were characterized. Scanning electron microscopy of the starch granules showed they were oval and polygonal in shape. Centric birefringence was clearly observed when viewed under polarized light. The gelatinization temperature range was 61–64–70.5 °C. The iodine affinity value (4.12%) indicated an amylose content of 21.68%. Brabender amylograms showed a fairly high maximum viscosity and very low breakdown, indicating high hot stability of the viscosity. The starch underwent a single‐stage swelling power pattern over one temperature range, and the solubility pattern paralleled the swelling power. The X‐ray diffraction pattern of the starch showed a Ca‐type crystallite. The gel chromatogram of the starch demonstrated the polydispersity of its molecular weight distribution.
Inhibitory activity of brown algal phlorotannins against hyaluronidase
Authors: Shibata Toshiyuki , Fujimoto Ken , Nagayama Kohki , Yamaguchi Kuniko , Nakamura Takashi
Published: March 2003

The inhibitory effect of brown algal phlorotannins on hyaluronidase was evaluated by an in vitro assay. Crude phlorotannins from the brown algae Eisenia bicyclis and Ecklonia kurome had a stronger inhibitory effect than well‐known inhibitors such as catechins and sodium cromoglycate. IC50 values of the following six phlorotannins: phloroglucinol, an unknown tetramer, eckol (a trimer), phlorofucofuroeckol A (a pentamer), dieckol and 8,8′‐bieckol (hexamers), were 280, 650, >800, 140, 120 and 40 μM, respectively. The IC50 of catechin, epigallocatechin gallate and sodium cromoglycate was 620, 190 and 270 μM, respectively. 8,8′‐Bieckol, the strongest HAase inhibitor in this study, acted as a competitive inhibitor with an inhibition constant (Ki) of 35 μM. Acetylation of the phlorotannins markedly decreased their inhibitory potency.
The production of clusters in milk chocolate
Authors: Nováková Hana , Čopíková Jana , Maixner Jaroslav , Maryška Martin
Published: March 2003

Cluster production during conching of milk chocolate leads to defects in chocolate quality. Various conditions of conching, using two types of milk chocolate were examined. Temperature and relative humidity were the parameters that were controlled. The contents of moisture, fat, sucrose and lactose and also cluster development in milk chocolate during conching were evaluated. Representative samples in the conching tests were subjected to particle size analysis (using laser diffraction and sieve methods), X‐ray diffraction analysis, polarizing microscopy and sensory evaluation.
Minerals and phytic acid interactions: is it a real problem for human nutrition?
Authors: Lopez H. Walter , Leenhardt Fanny , Coudray Charles , Remesy Christian
Published: March 2003

Summary Because of its high density of negatively charged phosphate groups, phytic acid (PA) forms very stable complexes with mineral ions rendering them unavailable for intestinal uptake. Indeed, the first step in mineral absorption requires that the mineral remains in the ionic state. As the PA content of the diet increases, the intestinal absorption of zinc, iron and calcium decreases. The inhibitory effects of PA on magnesium or copper are more controversial. Nevertheless, PA does not occur alone in foods and is often consumed with various compounds. Phytates are always present in vegetal matrix composed of fibres, minerals, trace elements and other phytomicronutrients. Thus, in order to evaluate mineral absorption from phytate‐rich products, all components of diet and food interactions should be considered and it is hard to predict mineral bioavailability in such products by using only the phytate content.
Anti‐cancer function of phytic acid
Authors: Shamsuddin Abulkalam M.
Published: March 2003

Summary Inositol hexaphosphate (InsP6 a.k.a. phytic acid or IP6) is ubiquitous. In the plant kingdom it is particularly abundant in cereals and legumes; in much smaller amounts IP6 and its lower phosphorylated forms (IP1−5) are contained in most mammalian cells, where they are important in regulating vital cellular functions. Both in vivo and in vitro experiments have demonstrated striking anticancer (preventive as well as therapeutic) effects of IP6. Inositol also is anti‐carcinogenic, albeit to a lesser extent; it acts synergistically IP6 in inhibiting cancer. In addition to reduction in cell proliferation, IP6 increases differentiation of malignant cells often resulting in reversion to the normal phenotype. IP6 is quickly absorbed from the rat stomach and upper intestine and distributed as inositol and IP1. In vitro, it is instantaneously taken up by malignant cells undergoing variable dephosphorylation to inositol and IP1−5, pointing towards their role in mediating the action of IP6. In humans, IP6 has recently been detected in urine, plasma and other biological fluids; the levels fluctuating with ingestion or deprivation of IP6 or IP6‐rich diet. As IP6 is high in high‐fibre diets, these also may explain, at least in part, the epidemiological observation showing the association of ingesting high‐fibre diets with a lower incidence of certain cancers. Along with safety, the reproducible efficacy of IP6 and inositol in the prevention of cancer in laboratory animals warrant their inclusion in our strategies for cancer prevention and perhaps therapy in humans. Aside from the anticancer action, IP6 and inositol also have numerous other health benefits. All these facts of normal physiological presence of IP6 in our body the level of which fluctuates with intake, association of an IP6‐rich diet with low incidence of several diseases and vice versa, and finally reversal of some of these conditions, at least in part, by IP6 supplementation strongly argue in favour of its inclusion as an essential nutrient or perhaps a vitamin.
A review of physical and chemical protein‐gel induction
Authors: Totosaus Alfonso , Montejano José G. , Salazar Juan A. , Guerrero Isabel
Published: March 2003

Summary Protein gelation is important to obtain desirable sensory and textural structures in foods. Gelation phenomenon requires a driving force to unfold the native protein structure, followed by an aggregation retaining a certain degree of order in the matrix formed by association between protein strands. Protein gelation has been traditionally achieved by heating, but some physical and chemical processes form protein gels in an analogous way to heat‐induction. A physical means, besides heat, is high pressure. Chemical means are acidification, enzymatic cross‐linking, and use of salts and urea, causing modifications in protein–protein and protein–medium interactions. The characteristics of each gel are different and dependent upon factors like protein concentration, degree of denaturation caused by pH, temperature, ionic strength and/or pressure.
Effect of genetically modified low phytic acid plants on mineral absorption
Authors: Mendoza Concepción
Published: March 2003

The reduction of phytic acid content in grains by genetic manipulation is a novel approach to increase mineral absorption from food based diets. Low phytic acid corn (Zea mays), rice (Oryza sativa), barley (Hordeum vulgare) and soybean (Gycine max) genotypes have been generated and mineral absorption has been evaluated. Genetically modified low phytic acid plants could be a novel contribution to the reduction of micronutrient malnutrition and animal waste phosphorus. Nevertheless, additional research needs to be done to understand the molecular biology and genetics of phytic acid accumulation during seed development, the negative and positive roles of dietary phytic acid in human health and the feasibility and effectiveness of the sustainable implementation of this approach at the community level.
Phytogenic and microbial phytases in human nutrition
Authors: Sandberg Ann‐Sofie , Andlid Thomas
Published: March 2003

Phytate (inositol hexa phosphate) hydrolysis can occur during food preparation and production and in the intestine, either by phytase from plants, yeasts or other micro‐organisms. This degradation is of nutritional importance, because removal of phosphate groups from the inositol ring results in an increased bioavailability of essential dietary minerals. To substantially improve iron absorption the degradation has to be virtually complete. Food processing techniques increasing the activity of the naturally occurring plant phytases are soaking, malting, hydrothermal treatment and fermentation. An alternative is addition of phytases or micro‐organisms producing phytase. Phytate degradation in the stomach and small intestine occurs as a result of activity of dietary phytase of plant or microbial origin. The plant phytase is less stable than fungal phytase in the physiological conditions of the intestine. Biotechnologically produced phytases may be possible for use tomorrow in food processing as well as plant raw material and starter cultures with inserted phytase genes.
Microbial phytase combined with amino acid supplementation reduces P and N excretion of growing and finishing pigs without loss of performance
Authors: Walz Othmar P. , Pallauf Josef
Published: March 2003

Summary The objective of this study was to evaluate the effect of a combined low‐protein (CP) low‐phosphorus (P) diet, supplemented with limiting amino acids and microbial phytase, on performance, nutrient utilization and carcass assessment of grower–finisher barrows. 4 × 6 crossbreed barrows were continuously housed in metabolism cages from 25 to 100 kg live weight and were fed diets, either conventional according to recent nutrient recommendations (A) or protein reduced (B) or protein and phosphorus reduced diets (C) based on barley (59–80%), maize (15%) and soybean meal (23–2%). Diet A (positive control) contained in fresh matter 18.5%, 15.6% and 13.6% CP and 0.59%, 0.51%, 0.50% P (growth phases I: 25–50 kg, II: 50–75 kg, III: 75–100 kg weight). Diet B was low in CP (14.2%, 13.4%, 11.0%), diet C low in CP and low in P (CP: as B, P: 0.46%, 0.41%, 0.32%). Diet D served as a negative control (CP and P as C). To diet B the limiting amino acids lysine, methionine, threonine and trypthophan were added to meet the levels in diet A, to diet C the limiting amino acids and 800 FTU Aspergillus‐phytase per kg were supplemented. At the end of the balance periods of about 100 (A,B,C) or 133 (D) days, the barrows were slaughtered at 100 kg live weight, the carcasses scored and loin, biceps femoris, os femoris and phalanx prima IV were analysed for their nutrient (dry matter, protein, fat) or mineral (ash, Ca, P, Mg, Fe, Zn) composition. In contrast to the basal diet D, the CP or P reduction in diets B and C did not negatively affect growth, feed efficiency, nitrogen retention or overall carcass performances of the pigs. With the low CP diets B and C, N excretion via the urine was significantly reduced and thus N excretion per unit weight gain was decreased by about 30%. The addition of microbial phytase (C) increased apparent digestibility of P significantly between 25% (growth phase III) and 50% (growth phase II). In spite of 25% reduction of P intake (C), the absolute daily P retention did not differ between treatments. Thus phytase supplementation in diet C reduced P excretion per unit weight gain by about 35% (I, II) to 44% (III) as compared with A and B. Similarly, phytase raised apparent digestibility of Ca by about 25% and Zn by about 80%. Generally, the carcass and meat characteristics were not affected by any of the diet strategies employed in this experiment. Mineralization (bone weight, ash, Ca, P, Mg) of the os femoris and phalanx prima IV were also similar in all treatment groups. However, phytase supplementation led to significantly increased zinc concentration in bones, indicating considerably improved zinc release from the phytate complex. In contrast, Fe incorporation into the os femoris was significantly reduced in the phytase group. In general, the low CP and low P feeding regimen introduced in this experiment offers substantial benefits in maintaining a sustainable environmentally‐friendly pork production.
Recovery of lysine and tryptophan from fortified nixtamalized cornflour and tortillas
Authors: Waliszewski Krzysztof N. , Estrada Yokiushirdhilgilmara , Pardio Violeta
Published: March 2003

Summary It has been shown, by sensory panels and tests on colour changes, that tortillas, enriched by nixtamalized cornflour, are acceptable for consumption and could supply up to 83% of Food and Agricultural Organization (FAO) recommended levels of lysine and tryptophan. We studied recovery of lysine and tryptophan which had been used to fortify nixtamalized cornflour and tortillas, which had been stored for 2 months at an ambient temperature of 30 °C. Three different levels of fortification of lysine and tryptophan, 83, 100 and 150% of the FAO recommended amounts, were used. Cornflour enriched with lysine and tryptophan did not lose important amounts of these amino acids after storage for up to 2 months at room temperature. Perhaps this was caused by the process of nixtamalization, which removed many reactive low molecular compounds normally present in corn and which could react with the free amino acids added for enrichment.
Addition of pectolytic enzymes: an enological practice which improves the chromaticity and stability of red wines
Authors: Revilla I. , González‐San José M. L.
Published: March 2003

Summary The effect of the addition of four commercial pectolytic preparations on the visual characteristics (colour and turbidity) of red wines has been evaluated. The effect of both clarifying and colour extracting enzymes and the effect of different doses used, were evaluated and compared. All the red wines treated enzymatically, independent of the type of enzyme and dose, present chromatic characteristics which can be considered better than those of the control wines. Also, those wines treated with enzymes had greater stability during 2 years storage in bottles, in particular the turbidity was better than untreated wines.