title: Decoloured Bloodmeal Based Bioplastic

authors: Low, Aaron

subjects: Bloodmeal

abstract: Renewable and compostable bioplastics can be produced from biopolymers such as proteins. Animal blood is a by-product from meat processing and is rich in protein. It is dried into low value bloodmeal and is used as animal feed or fertiliser. Previous work has shown that bloodmeal can be converted into a thermoplastic using water, urea, sodium dodecyl sulphate (SDS), sodium sulphite and triethylene glycol (TEG). This material is currently being commercialised as Novatein Thermoplastic Protein (NTP) and studies are working on improving its properties through production of composites and blends. In addition further studies are working on understanding its molecular structure before and after thermoplastic processing by utilising various analytical techniques.

A specific area identified for improvement is its colour and smell. NTP is black in colour and has an offensive odour which means its current potential applications are limited to agriculture and waste disposal. Approximately 30 to 40% of plastics are used in short life span applications such as packaging and using bioplastics in these applications would be advantageous because of their compostability. To increase NTP’s possible range of applications to common applications such as packaging and increase its acceptance from consumers, its colour and odour must be removed without compromising its mechanical properties.

Oxidative treatment methods for removing colour and odour from red blood cell concentrate (RBCC), modified red blood cell concentrate (mRBCC) and bloodmeal were investigated using hydrogen peroxide, peracetic acid (PAA), sodium hypochlorite, sodium chlorite, sodium chlorate and chlorine dioxide.  Treatment effect on protein molecular weight, crystallinity, thermal stability, solubility, product colour and smell were investigated.  Treating RBCC and mRBCC required multiple processing steps, had high water contents  (67% and 93% respectively), foamed during treatment with peroxides and the protein was prone to hydrolysis.  Bloodmeal contained 95% solids and was less sensitive to hydrolysis.  

The best decolouring and deodorising results were obtained by treating bloodmeal with 5% PAA.  Using this novel treatment method, decolouring was completed within five minutes and produced a powder which was 67% white based on the RGB colour scale.  Protein molecular weight was unaffected by PAA concentration, with a number average molecular weight ranging between 190-223 kDa for 1-5% PAA treated bloodmeal. However, its crystallinity decreased from 35% to 31-27% when treated with 1-5% PAA. Treating bloodmeal with 1-5% PAA also reduced the protein’s thermal stability, glass transition temperature (225°C down to 50°C) and increased its solubility from 11% to 85% in 1% SDS solution at 100°C.

3-5% PAA treated bloodmeal powder was extruded using different combinations of water, TEG, glycerol, SDS, sodium sulphite, urea, borax, salt and sodium silicate at concentrations up to 60 parts per hundred parts bloodmeal (pphBM).  Partially consolidated extrudates and fully consolidated injection moulded samples were obtained using a combination of water, TEG and SDS. 4% PAA treated bloodmeal produced the best extruded and injection moulded samples and was chosen for investigating the effects of water, TEG and SDS concentration on consolidation and specific mechanical energy input (SME) as well as product colour and mechanical properties.  

Analysis of variance (ANOVA) showed SDS was the most important factor influencing ability to be extruded because it detangled protein chains and allowed them to form new stabilising interactions required for consolidation. The best extruded sample, which was 98% consolidated and 49% white, contained 40 pphBM water, 10 pphBM TEG and 6 pphBM SDS.
  
TEG had the greatest effect on the product’s mechanical properties and colour after injection moulding because of its plasticisation effect. ANOVA showed TEG contributed 30.5% to changes in Young’s modulus, 66.9% to strain, 39.7% to toughness, 0.1% to UTS and 38.1% to colour. However, SDS also contributed 8.1% to changes in Young’s modulus, 13.7% to strain, 15.2% to toughness, 12.5% to UTS, 0.5% to colour. Initial water content contributed 19.7% to Young’s modulus, 1.0% to strain, 0.6% to toughness, 30.0% to UTS and 29.9% to colour. The best injection moulded sample was produced using 50 pphBM water, 20 pphBM TEG and 3 pphBM SDS.  This produced a material which was 39% white, which had an almost transparent yellow/orange colour with a tensile strength of 4.62 MPa, Young’s modulus 85.48 MPa, toughness 1.75 MPa and 82.62% strain. 

The mechanical properties of the product manufactured in this study were comparable to those of NTP, but the product was mostly decoloured, allowing it to be easily pigmented and without an offensive odour.

text: Decoloured Bloodmeal Based Bioplastic Renewable and compostable bioplastics can be produced from biopolymers such as proteins. Animal blood is a by-product from meat processing and is rich in protein. It is dried into low value bloodmeal and is used as animal feed or fertiliser. Previous work has shown that bloodmeal can be converted into a thermoplastic using water, urea, sodium dodecyl sulphate (SDS), sodium sulphite and triethylene glycol (TEG). This material is currently being commercialised as Novatein Thermoplastic Protein (NTP) and studies are working on improving its properties through production of composites and blends. In addition further studies are working on understanding its molecular structure before and after thermoplastic processing by utilising various analytical techniques.

A specific area identified for improvement is its colour and smell. NTP is black in colour and has an offensive odour which means its current potential applications are limited to agriculture and waste disposal. Approximately 30 to 40% of plastics are used in short life span applications such as packaging and using bioplastics in these applications would be advantageous because of their compostability. To increase NTP’s possible range of applications to common applications such as packaging and increase its acceptance from consumers, its colour and odour must be removed without compromising its mechanical properties.

Oxidative treatment methods for removing colour and odour from red blood cell concentrate (RBCC), modified red blood cell concentrate (mRBCC) and bloodmeal were investigated using hydrogen peroxide, peracetic acid (PAA), sodium hypochlorite, sodium chlorite, sodium chlorate and chlorine dioxide.  Treatment effect on protein molecular weight, crystallinity, thermal stability, solubility, product colour and smell were investigated.  Treating RBCC and mRBCC required multiple processing steps, had high water contents  (67% and 93% respectively), foamed during treatment with peroxides and the protein was prone to hydrolysis.  Bloodmeal contained 95% solids and was less sensitive to hydrolysis.  

The best decolouring and deodorising results were obtained by treating bloodmeal with 5% PAA.  Using this novel treatment method, decolouring was completed within five minutes and produced a powder which was 67% white based on the RGB colour scale.  Protein molecular weight was unaffected by PAA concentration, with a number average molecular weight ranging between 190-223 kDa for 1-5% PAA treated bloodmeal. However, its crystallinity decreased from 35% to 31-27% when treated with 1-5% PAA. Treating bloodmeal with 1-5% PAA also reduced the protein’s thermal stability, glass transition temperature (225°C down to 50°C) and increased its solubility from 11% to 85% in 1% SDS solution at 100°C.

3-5% PAA treated bloodmeal powder was extruded using different combinations of water, TEG, glycerol, SDS, sodium sulphite, urea, borax, salt and sodium silicate at concentrations up to 60 parts per hundred parts bloodmeal (pphBM).  Partially consolidated extrudates and fully consolidated injection moulded samples were obtained using a combination of water, TEG and SDS. 4% PAA treated bloodmeal produced the best extruded and injection moulded samples and was chosen for investigating the effects of water, TEG and SDS concentration on consolidation and specific mechanical energy input (SME) as well as product colour and mechanical properties.  

Analysis of variance (ANOVA) showed SDS was the most important factor influencing ability to be extruded because it detangled protein chains and allowed them to form new stabilising interactions required for consolidation. The best extruded sample, which was 98% consolidated and 49% white, contained 40 pphBM water, 10 pphBM TEG and 6 pphBM SDS.
  
TEG had the greatest effect on the product’s mechanical properties and colour after injection moulding because of its plasticisation effect. ANOVA showed TEG contributed 30.5% to changes in Young’s modulus, 66.9% to strain, 39.7% to toughness, 0.1% to UTS and 38.1% to colour. However, SDS also contributed 8.1% to changes in Young’s modulus, 13.7% to strain, 15.2% to toughness, 12.5% to UTS, 0.5% to colour. Initial water content contributed 19.7% to Young’s modulus, 1.0% to strain, 0.6% to toughness, 30.0% to UTS and 29.9% to colour. The best injection moulded sample was produced using 50 pphBM water, 20 pphBM TEG and 3 pphBM SDS.  This produced a material which was 39% white, which had an almost transparent yellow/orange colour with a tensile strength of 4.62 MPa, Young’s modulus 85.48 MPa, toughness 1.75 MPa and 82.62% strain. 

The mechanical properties of the product manufactured in this study were comparable to those of NTP, but the product was mostly decoloured, allowing it to be easily pigmented and without an offensive odour.

year: 2012

title: Freshwater mussels as bioindicators of faecal contamination

authors: Tawhai, Valletta Angela

subjects: mussels

abstract: Mussels (Hyridella menziesi) were tested for their suitability as monitors of bacterial contamination of natural waters because of their ability to accumulate bacteria while
filtering the environment for food. Several questions were addressed :
1. Can E. coli be recovered from mussels immersed in low-density suspensions of bacteria.
2. What is the optimum time required to immerse mussels in suspension of bacteria.
3. How long will the mussels retain bacteria once uptake had occurred.
4. Is it possible to estimate the numbers of bacteria present in contaminated waters, Using the numbers of bacteria recovered from mussels.
The Results of this study were :
1. It was possible to detect E. coli and Salmonella in mussels that had been immersed in water contaminated with these bacteria at densities as low as around 50 per 100 ml.
2. An experiment conducted to examine the ability of mussels to retain bacteria once uptake had occurred, showed there was rapid loss of E.coli (42.9%) over the first 4 hours and by 6 hours numbers had declined to very low levels (2.1 %).
3. Although there was some evidence of a correlation between the concentration of E. coli present in surrounding waters and the numbers recovered from mussels
it was not possible to predict the numbers of bacteria in the surrounding water from analysis of the mussels.
4. Similar experiments were done using diluted sewage instead of pure cultures of E. coli and Salmonella. Results were similar to those obtained using pure cultures. E. coli could be recovered from mussels when present in the diluted sewage at concentrations as low as 8 / ml.

text: Freshwater mussels as bioindicators of faecal contamination Mussels (Hyridella menziesi) were tested for their suitability as monitors of bacterial contamination of natural waters because of their ability to accumulate bacteria while
filtering the environment for food. Several questions were addressed :
1. Can E. coli be recovered from mussels immersed in low-density suspensions of bacteria.
2. What is the optimum time required to immerse mussels in suspension of bacteria.
3. How long will the mussels retain bacteria once uptake had occurred.
4. Is it possible to estimate the numbers of bacteria present in contaminated waters, Using the numbers of bacteria recovered from mussels.
The Results of this study were :
1. It was possible to detect E. coli and Salmonella in mussels that had been immersed in water contaminated with these bacteria at densities as low as around 50 per 100 ml.
2. An experiment conducted to examine the ability of mussels to retain bacteria once uptake had occurred, showed there was rapid loss of E.coli (42.9%) over the first 4 hours and by 6 hours numbers had declined to very low levels (2.1 %).
3. Although there was some evidence of a correlation between the concentration of E. coli present in surrounding waters and the numbers recovered from mussels
it was not possible to predict the numbers of bacteria in the surrounding water from analysis of the mussels.
4. Similar experiments were done using diluted sewage instead of pure cultures of E. coli and Salmonella. Results were similar to those obtained using pure cultures. E. coli could be recovered from mussels when present in the diluted sewage at concentrations as low as 8 / ml.

year: 2000

title: Oranga whānau, oranga niho: The oral health status of 5-year-old Māori children. A case study

authors: Te Amo, Kirstin Mei

subjects: Maori health

abstract: Research has shown that the oral health of Māori is far worse than non-Māori across all
age groups. The objective of this research study was to assess the dental wellbeing of
5-year olds with a specific focus on Māori children currently residing in the Hamilton City
region. In addition, this research focused on the impact that social, economic, cultural
and environmental factors have on oral health. A total of 32 participants were invited to
take part in this research: 15 5-year-old children from three selected schools, 15 (of the
children's) caregivers and 2 dental therapists who work in the Hamilton City region.
The findings indicated that overall Māori children and children of lower socio-economic
status had a much higher prevalence of dental caries (tooth decay) than non-Māori
children and children of higher socio-economic status. A number of contributing factors
were shown to be responsible for this disparity including the cultural inappropriateness
of oral health services and resources, affordability, role-modelling, parental awareness
and education, and the transient nature of families.
It was found that no one strategy or intervention will achieve dramatic improvements in
Māori oral health as a concerted effort is required by Local and Central Government, the
Health Sector and Māori communities.

text: Oranga whānau, oranga niho: The oral health status of 5-year-old Māori children. A case study Research has shown that the oral health of Māori is far worse than non-Māori across all
age groups. The objective of this research study was to assess the dental wellbeing of
5-year olds with a specific focus on Māori children currently residing in the Hamilton City
region. In addition, this research focused on the impact that social, economic, cultural
and environmental factors have on oral health. A total of 32 participants were invited to
take part in this research: 15 5-year-old children from three selected schools, 15 (of the
children's) caregivers and 2 dental therapists who work in the Hamilton City region.
The findings indicated that overall Māori children and children of lower socio-economic
status had a much higher prevalence of dental caries (tooth decay) than non-Māori
children and children of higher socio-economic status. A number of contributing factors
were shown to be responsible for this disparity including the cultural inappropriateness
of oral health services and resources, affordability, role-modelling, parental awareness
and education, and the transient nature of families.
It was found that no one strategy or intervention will achieve dramatic improvements in
Māori oral health as a concerted effort is required by Local and Central Government, the
Health Sector and Māori communities.

year: 2007