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Item Understanding the Effects of Lactose Hydrolysis Modeling on the Main Oligosaccharides in Goat Milk Whey Permeate(MDPI (Basel, Switzerland), 2019-09-10) Thum C; Weinborn V; Barile D; McNabb WC; Roy NC; Leite Nobrega de Moura Bell JM; Moreno DA; Villaño DEnzymatic hydrolysis of lactose is a crucial step to improve the efficiency and selectivity of membrane-based separations toward the recovery of milk oligosaccharides free from simple sugars. Response surface methodology was used to investigate the effects temperature (25.9 to 54.1 °C) and amount of enzyme (0.17 to 0.32% w/w) at 1, 2, and 4 h of reaction on the efficiency of lactose hydrolysis by Aspergillus oryzae β-galactosidase, preservation of major goat whey oligosaccharides, and on the de-novo formation of oligosaccharides. Lactose hydrolysis above 99% was achieved at 1, 2, and 4 h, not being significantly affected by temperature and amount of enzyme within the tested conditions. Formation of 4 Hexose (Hex) and 4 Hex 1 Hex and an increased de-novo formation of 2 Hex 1 N-Acetyl-Neuraminic Acid (NeuAc) and 2 Hex 1 N-Glycolylneuraminic acid (NeuGc) was observed in all treatments. Overall, processing conditions using temperatures ≤40 °C and enzyme concentration ≤0.25% resulted in higher preservation/formation of goat whey oligosaccharides.Item Complexation between whey protein and octenyl succinic anhydride modified starch: a novel approach for encapsulation of lipophilic bioactive compounds : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Manawatū, New Zealand(Massey University, 2018) Wu, DanProteins and polysaccharides are frequently used in food industry, and their interactions in food systems could affect the properties of food products such as the texture and stability. Therefore, the knowledge of the interactions between these two macromolecules is of great significance for food manufacturers. The aim of this study was to investigate the complexation process between whey protein isolate (WPI) and octenyl succinic anhydride (OSA)-modified starch and explore the application of their interactions in the encapsulation of lipophilic bioactive compounds. The formation of complexes between WPI and OSA-modified starch was investigated as a function of pH (7-3), the heat treatment of WPI, and the concentration ratio of WPI and OSA-modified starch (1:1, 1:10 and 1:20). The complexation process was evaluated by the determinations of the absorbance, particle size and ζ-potential of the mixtures, which were determined by spectrophotometer and dynamic light scattering. It was found that the OSA-modified starch was more likely to interact with heated WPI (HWPI, 90°C for 20 min) rather than non-heated WPI (NWPI). The optimum condition for the formation of insoluble coacervates was at ratio of 1:10 and pH 4.5, which was driven by both electrostatic and hydrophobic interactions. The structure of the complexes formed under the optimum condition could be affected by different molecular characteristics of OSA-modified starch including molecular weight (Mw) and degrees of substitution (DS) value. It was found that OSA-modified starch with higher Mw was difficult to form a dense precipitation phase with HWPI due to its higher viscosity restricting the movement of any particles present. Stable soluble complexes could be formed between HWPI and OSA-modified starch with higher DS value under the same condition, which may be attributed to the stronger steric hindrance of OSA-modified starch with higher DS values. It seems that the complexation between HWPI and OSA-modified starch was induced by electrostatic interactions, while the structural properties of the complexes were determined by hydrophobic interactions. The soluble complexes between HWPI and OSA-modified starch with a DS value of 4.29 ± 0.11% formed at ratio of 1:10 and pH 4.5 were applied to encapsulate β-carotene, which was used as a model of lipophilic bioactive compounds in this study. The apparent aqueous solubility of β-carotene was enormously improved (264.05±72.53 μg/g) after encapsulation in the soluble complexes. No significant differences were observed under transmission electron microscopy (TEM) and scanning electron microscope (SEM) between the soluble complexes before and after encapsulation of β-carotene whether in a liquid or a powdered form. Results of Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) indicated that the β-carotene was in an amorphous form loaded inside the soluble complexes, which suggested that the molecules of β-carotene evenly distribute within the complex particles by hydrophobic force. In addition, the β-carotene-loaded freeze-dried soluble complexes showed good redispersion behaviour and a high retention rate of the loaded β-carotene (89.75%), which indicated that the β-carotene-loaded soluble complexes could be successfully converted into a powdered form. The accelerated stability study showed that these soluble complexes could effectively protect the loaded β-carotene at pH 4.5 during storage, especially after 7 days of storage. This indicated the potential of using the soluble complexes between HWPI and OSA-modified starch to protect lipophilic bioactive compounds for long-term storage under low pH conditions. This study may be beneficial for the potential using the soluble complexes between HWPI and OSA-modified starch as delivery systems for lipophilic bioactive compounds in commercial applications.Item Selective removal of fat from acid whey during whey protein concentrate manufacture : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Technology in Food Technology(Massey University, 2000) Harford, ArronThe purpose of this study was to develop a low cost technology for selective removal of lipids from acid whey during whey protein concentrate manufacture Attention was focused on gaining a better understanding of the structure and composition of the lipids in whey and ultrafiltration retentate The effects of varying dilutions, pH, salt concentration, temperature and holding time on the flocculation of lipids in the whey and retentate were investigated The composition and structure of lipids in acid whey and retentate were determined by ultracentrifugation, compositional analysis, integrated light scattering and confocal scanning laser microscopy (CLSM) techniques. Acid whey contained ~ 0.034% lipids The size of the milk fat globules (MFG) in whey varied from 0.1 and 10 μm. with the majority of the globules < 1 μm in diameter The retentate contained ~ 0.36% lipids The size of the MFG in the retentate ranged between 0.1 and 20 μm. generally larger than the MFG in the acid whey Investigation into the removal of lipids from acid whey revealed that flocculation of MFG in the acid whey occurred at temperatures between 40 and 50°C and at pH values from 5.8 to 7.0. It was observed that under these conditions, high-density lipid containing flocculent/precipitates was formed, which subsequently sedimented upon centrifugation (at 1126/g for 10 min) The MFG removed in the flocculent/precipitate appears to be either part of a calcium-MFG complex or MFG entrapped by precipitation of calcium precipitate Examination of the effects of physiochemical factors on the flocculation of MFG in between the retentate revealed that flocculation occurred upon dilution and at pH values between 4.5 and 4.7. It was found that at increasing dilutions, there was an increase in the removal of MFG and in the retention of protein in the supernatant. At retentate dilution of 1:6, the majority of the MFG was removed and a majority of protein was retained in the supernatant Flocculation of MFG in the diluted retentate was influenced by ionic strength (at Low pH values) of the system. This flocculation is thought to result from the hydrophobic association of proteins of MFGM, aggregates of serum proteins, lipoprotein complexes or individual denatured serum proteins Low fat whey protein concentrate powder (WPC) was produced on a pilot-scale plant using the process conditions determined at the laboratory scale to remove MFG from acid whey retentate. The resulting product contained ~ 1% fat. considerably less than the normal commercial WPC On a dry basis the protein content was ~ 96% as compared to ~ 85% in the commercial WPC Examination of the functionality of the low fat WPC revealed the heat-induced gels formed from 15% WPC were more elastic, had better water holding capacity, and were more "gelatinous" in nature Their gelation properties were markedly superior to the commercial WPCs currently manufactured Based on the results of this study, recommendations are made on possible areas of process improvement and development opportunities.Item The immobilization of Kluyveromyces fragilis and Saccharomyces cerevisiae in polyacrylamide gel : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Biotechnology at Massey University(Massey University, 1980) Dillon, Judith AnnThe search for new energy sources has indicated that biomass, in the form of green plant materials and biological wastes, can provide a perpetual energy source if converted to a useful form. This study investigated the production of ethanol by the fermentation of sugars using immobilized cells. The experimental procedure involved the immobilization of two yeast species, Kluyveromyces fragilis NRRL Y 1109 and Saccharomyces cerevisiae NCYC 240, in polyacrylamide gel for the fermentation of lactose and glucose respectively. The gel methodology of two previous authors, Chibata et al. (1974) and Neuhoff (1973) was used. The former author's gel was used as a basis for batch experiments to determine the gel composition for maximum ethanol producing activity by both cell species as initial trials with this gel yielded encouraging results. Variations in monomer, BIS and cell concentration revealed that a gel containing 15% (w/v) acrylamide, 1.5% (w/v) BIS and 25% (w/v) cells in addition to 0.6% (w/v) BDMAP and 0.25% (w/v) ammonium persulfate in tris-HCl buffer pH 7.1 polymerised at 0°C produced the greatest activity in immobilized K. fragilis cells with an activity retention for immobilization of 80%. The gel composition for greatest activity in immobilized S. cerevisiae cells differed only slightly from that above containing 20% (w/v) acrylamide, 1.6% (w/v) BIS and 40% (w/v) cells and resulted in a 46% activity retention for immobilization. Further experiments at various substrate concentrations indicated that the gel imposed small or negligible limitations on the diffusion of substrate and product. Experiments to increase the cell activity retention for the immobilization of S. cerevisiae using the Neuhoff (1973) gel were unsuccessful but produced some important results. It was found that exposure to gel components, especially to the acrylamide monomer, reduced the ethanol producing ability and the viability of the cells. The general protective agents Tween 80, glycerol, gelatin and dithiothreitol proved ineffective. To minimize this damage to the cells the gels were polymerised at 0°C with rapid polymerisation being induced by high initiator and accelerant concentrations. Repeated use of the immobilized cells indicated that the simple substrate medium, of the suqar in distilled water used previously, was not sufficient to maintain stable ethanol producing activity. Although trials involving supplementation with a salt solution were unsuccessful, the incorporation 0.5% (w/v) peptone in the medium and the use of protein-containing media, such as whey, was found to stabilize activity. Experiments in continuous processing revealed that immobilized K. fragilis cells produced ethanol from deproteinised whey at an efficiency of 70 to 80% over extended periods with complete substrate utilization of full strength whey being achieved at flowrates of 0.15 SV. The half life of the activity of the immobilized cells was estimated to be at least 50 days. The experimental results suggest that this approach to fermentation may be industrially acceptable for the production of ethanol. However, a costing exercise on the production of ethanol from whey indicates that unless the product is a highly priced commodity, such as a pharmaceutical, the process is unlikely to be economically feasible due to the high cost of the immobilization support monomer.Item Application of alternative fermenter design in whey-ethanol production (a preliminary study) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Biotechnology at Massey University(Massey University, 1995) Tin, Calvin Siu FanThe performance of a crossflow-microfiltration recycle reactor for whey-ethanol production was studied. Experiments using the yeast strain Kluyveromyces marxianus Y-113, an industrial whey-ethanol strain, and reconstituted acid whey permeate powder were carried out. Unsteady state experiments (i.e. with 100% cell recycle) were conducted at 46-137 g/l feed lactose concentration and dilution rates of 0.44-1.3 hr. These experiments were used to estimate the maximum specific growth rate (μ;), biomass substrate yield coefficient (Y), product substrate yield coefficient (Y). A mathematical model for biomass, lactose and ethanol concentration prediction was also developed. The model was based on Monid kinetics incorporating the concepts of a significant biomass volume fraction and single product inhibition. Two unsteady state experiments were conducted at 53.4-55.7 g/l lactose and dilution rate of 0.88-0.95 hr to check fermentation model accuracy. Two steady state runs at 64-110 g/l lactose, dilution rates of 0.34-0.43 hr were established for comparison with the unsteady state runs and to observe the effect of operation under stable conditions with the cell concentration regulated at 10 g/l.. Productivity increases of up to 13 times over the commercial batch fermentation process using the same organism was obtained. The highest productivity obtained was 13.7 g/l.hr. when the biomass was allowed to accumulate to 29.6 g/l, but lactose utilization (46%) and ethanol concentration (10.5 g/l) were low. In general, lower values of substrate utilization and ethanol concentration were noted at high dilution rates. At high feed lactose concentrations, lower lactose utilization was obtained. It was also noted that the growth rate was not significantly affected by substrate concentration and dilution rate. The product substrate coefficient (Y) was affected by dilution rate but independent of lactose concentration. Increasing dilution rate also decreased the biomass yield coefficient (Y) and the product substrate yield coefficient (Y). Further experiments are needed to better understand the effects of these parameters on yield coefficients. Steady state runs showed close agreement to the corresponding unsteady state experiments. Major problem of the fermenter operation was insufficient membrane flux which resulted in short fermentation runs at some condition. To solve this problem, a dual membrane configuration coupled with a permeate back flushing mechanism should be introduced. The mathematical model developed was adequate, but not optimal, an uncertainties of ± 30% and ± 20% in prediction of lactose and biomass concentrations were noted. While this was acceptable in the context of preliminary economic analysis and process optimization, to further improve the model accuracy, a relationship between the various yield coefficients and operating conditions has to be determined. Better estimation of the maximum specific growth rate (μ ) and incorporating a function to describe the variation of specific growth rate (μ) with biomass and ethanol concentrations is needed. More accurate estimation of the biomass substrate yield coefficient (Y) is also necessary for further model refinement. In conclusion, the crossflow-mircofiltration recycle fermenter has demonstrated potential application in whey-ethanol production with much improved productivity over current commercial and batch systems. Further studies are needed to determine its performance as compared to other intensive fermenter designs. The mathematical model developed also provides sufficient accuracy for preliminary process economic analysis and for process optimization study.Item Aggregation and gelation of bovine b-lactoglobulin, a-lactalbumin and serum albumin : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Food Technology at Massey University(Massey University, 1995) Gezimati, JacquelineGelation is one of the most important functional properties of whey proteins in food systems. The properties of whey protein gels are affected by the chemical and physical properties of its protein components, (β- lactoglobulin AB (β-Lg), α-lactalbumin (α-La) and bovine serum albumin (BSA). Heat-induced aggregation and gelation of individual whey proteins, (β-Lg, α-La and BSA and in mixture was studied by dynamic rheology and electrophoresis analysis. The proteins were dispersed in an ionic buffer containing 0.009 M CaCl , 0.012 M NaCl, 0.012 M K HPO and 0.007 M Nacitrate (pH 6.8) which was comparable to the ionic composition of 12% whey protein concentrate solution. Rheological properties of the protein solutions were measured using a Bohlin VOR rheometer after heating to 70, 75 and 80°C, holding at these temperatures for 60 min and after cooling to 25°C. Gel electrophoresis under non-dissociating (Native-PAGE in the absence of dissociating and reducing agents) and dissociating but non-reducing conditions (SDS-PAGE) was used to determine the extents of aggregation in some of the heated protein samples. Gelation temperatures of 10%, w/v, protein solutions were found to be in the range 82.5 - 84°C for β-Lg and 68 - 70°C for BSA while α-La did not gel even at 90°C. Gelation temperatures of protein mixtures containing β- Lg and BSA were dependent on the relative proportion of the two proteins in the mixture. In contrast, the protein mixtures containing β-Lg and α-La gelled at temperatures (~ 83°C) comparable to that of β-Lg alone. Rheological measurements on pure β-Lg and BSA showed that BSA solutions formed self-supporting gels at lower protein concentrations and lower temperatures. Increasing the heating temperature or protein concentration of either β-Lg or BSA resulted in higher values of the storage modulus (G'). It was apparent from the electrophoretic data that protein aggregates were formed as an intermediate prior to the formation of gel net-work. These aggregates appeared to be non-covalently linked initially and became increasingly disulphide-linked during heating. Analysis of mixtures containing β-Lg and BSA during heat treatment showed that at both 70 and 75°C the gelation time decreased with the increasing proportion of BSA. Similarly, the values of G' after 60 min of heating were greater for the gels containing more BSA. G' values of these mixtures were dependent on the heating temperature and the relative proportion of the two proteins. Gel electrophoresis data for a mixture of 5% β-Lg and 5% BSA heated at 70°C showed that prior to gelation most of the BSA had been transformed into aggregates while most of the β-Lg was essentially in the native form. Aggregates of both β-Lg and BSA were formed during heating at 75°C. At both temperatures, gelation commenced after most of the BSA had become covalently cross-linked but before all the β-Lg had become cross-linked. This effect was also apparent for other mixtures. Initially the aggregates appeared to be non-covalently linked and became increasingly disulphide linked with heating. From these results it is apparent that during heating at 70°C, BSA is the main protein forming the gel net-work and some β-Lg aggregates are probably attached to the net-work strand through either hydrophobic interactions or disulphide linkages. During heating at 75°C, two gel net-works are presumed to be formed independently, again with some interactions between the strands of the two net-works. The rheological properties of protein mixtures containing β-Lg and α-La showed that β-Lg was the dominant gelling protein. G' values decreased with increasing relative proportion of α-La in the mixture at both 75 and 80°C. Gelling times increased with increasing proportion of α-La in the mixture at both 75 and 80°C. No aggregate formation was observed during heating of α-La at 75 or 80°C. However, in the presence of β-Lg, α-La aggregated rapidly during heating. This aggregation appears to involve sulphydryl disulphide interchange reactions particulary when the mixtures were heated at 80°C. Almost all the proteins had aggregated through disulphide linkages before any significant increase in G'. It is suggested that during heating and prior to gelation co-polymers of both β-Lg and α-La were formed and this resulted in heterogeneous net-work strands being formed. The results presented in this study suggest that slight differences in the protein composition of WPC are unlikely to affect the gelation properties of WPC. Further studies into the effects of immunoglobulins (Igs) are needed in order to gain further understanding of the contributions of these proteins to rheological properties of WPC gels.Item Heat-induced interactions of [beta]-lactoglobulin, [alpha]-lactalbumin and casein micelles : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Education in Food Technology at Massey University(Massey University, 1996) Chiweshe, Martha ChogugudzaThe denaturation and aggregation of β-lactoglobulin and α-lactalbumin were studied in the following mixtures, designed to simulate the protein concentrations and ionic environment in normal skim milk. 1. β-lactoglobulin (0.4% w/v), 2. α-lactalbumin (0.15% w/v), 3. β-lactoglobulin (0.4% w/v) and casein micelles (~ 2.6% w/v), 4. α-lactalbumin (0.15% w/v) and casein micelles (~ 2.6% w/v), 5. β-lactoglobulin (0.4% w/v) and α-lactalbumin (0.15% w/v) and 6. β-lactoglobulin (0.4% w/v), α-lactalbumin (0.15% w/v) and casein micelles (~ 2.6% w/v) Proteins were dissolved in SMUF, pH 6.7, and heated at 80 and 95°C for various times and centrifuged at 100,000 g for 60 min. The supernatants and pellets obtained were analysed using gel electrophoresis under non-dissociating (Native-PAGE in the absence of dissociating and reducing agents), dissociating but non-reducing (SDSNR-PAGE) and dissociating and reducing conditions (SDSR-PAGE). When β-lactoglobulin was heated alone and examined by native-PAGE, the quantity of native protein decreased with increasing heating time at 80°C. Addition of α-lactalbumin to the β-lactoglobulin solution increased the loss of β-lactoglobulin during the initial stages of heating. Addition of casein micelles to the β-lactoglobulin solution markedly increased the loss of native β-lactoglobulin throughout the heating period. The loss of β-lactoglobulin from the mixture containing β-lactoglobulin, α-lactalbumin and casein micelles was similar to that from the mixture of β-lactoglobulin and casein micelles. The loss of β-lactoglobulin from these protein mixtures could be described by second-order reaction kinetics. Heating these mixtures at 95°C caused very rapid loss of native β-lactoglobulin, but the effects of the addition of casein micelles and α-lactalbumin were generally similar to those observed at 80°C. When α-lactalbumin was heated at 80°C either alone or in the presence of casein micelles, there was only a slight loss of the native α-lactalbumin. However the corresponding losses of native α-lactalbumin were considerable greater on heating at 95°C. At both temperatures, the addition of β-lactoglobulin increased the rate of loss of α-lactalbumin substantially. The addition of casein micelles to the mixture of α-lactalbumin and β-lactoglobulin had little further effect on the loss of native α-lactalbumin. The rates of loss of α-lactalbumin at 95°C in all mixtures could be adequately described by first-order kinetics. When β-lactoglobulin was heated either alone or in the presence of casein micelles and examined by SDSNR-PAGE, the loss of SDS-monomeric β-lactoglobulin was less than the loss of native β-lactoglobulin. In contrast, when α-lactalbumin was added to β-lactoglobulin or β-lactoglobulin and casein micelles mixture, the loss of SDS-monomeric β-lactoglobulin was comparable to that of native β-lactoglobulin. The difference between native and SDS-monomeric β-lactoglobulin represents aggregates that are linked by non-covalent (hydrophobic) interactions. Thus the protein mixtures containing α-lactalbumin, contain no or little non-covalently linked β-lactoglobulin aggregates, and consequently, all the β-lactoglobulin aggregates would be disulphide linked. The results for the loss of SDS-monomeric and native α-lactalbumin at 95°C showed that both non-covalent and disulphide-linked aggregates of α-lactalbumin were present in all the protein mixtures studied. When β-lactoglobulin solution was heated at 95°C, large aggregates were formed which could be sedimented at 100,000 g for 60 min. Addition of casein micelles to β-lactoglobulin solution caused greater sedimentation of β-lactoglobulin. Similar results were obtained when the mixture containing β-lactoglobulin, α-lactalbumin and casein micelles was heated at 95°C. In contrast, the mixture containing β-lactoglobulin and α-lactalbumin behaved in a similar manner to β-lactoglobulin alone. When α-lactalbumin was heated at 95°C alone or in the presence of casein micelles, it did not interact to form large sedimentable aggregates. However when β-lactoglobulin was added to the above protein solutions, there was a considerable increase in sedimentation of α-lactalbumin.Item A study of the effects of plane of nutrition on bovine milk proteins, with particular emphasis on the individual whey proteins : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University(Massey University, 1977) Gray, Robert MacauleyMilk and other dairy products comprise a major source of man's food. The milk of the cow (Bos taurus) is of overwhelming importance (F.A.O. Yearbook 1974). Interest in the composition of cows milk stems largely from its importance in the human diet and from the need of milk producers to meet the legal requirements governing its sale (Rook 1961a). Prior to about the 1850's milk had been found to contain fat, sugar, protein and minerals (Jenness and Patton 1959). The development and refinement of qualitative and quantitative techniques has subdivided these gross categories of milk composition into a vast array of molecules (jenness 1974). The composition of cows milk has been extensively reviewed: Cerbulis and Farrell (1975), Jenness (1974), Webb and Johnson (1965), Ling et al. (1961), Rook (1961a & b), Armstrong (1959), Jenness and Patton (1959). The Sale of Food and Drugs Act (l908) prescribed minimum compositional standards required for milk sold or intended for sale in New Zealand. These were"8.5 parts per centum of milk solids other than milk fat and 3.25 parts per centum of milk fat" (Sykes 1952).Item A study of the protein needs of growing pigs fed rations containing whey : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science, Massey University, New Zealand, 1967(Massey University, 1967) Carr, John RNo abstract availableItem The utilization of lactose by the growing pig : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science(Massey University, 1997) Shearer, Ian JohnThe results of a recent Nationwide survey (Davenport 1966) showed that 93% of all pig units were still dependent on supplies of liquid dairy by-products - whey and skim milk - for their major source of pig food. Calculations made from figures for cheese and casein production (N.Z. Govt. Statistics, 1967) show that in 1966, approximately 500 million gallons of whey alone, were produced. Of this, a comparatively small amount is utilized by the dairy industry to produce alternative by-products. Condensed or dried whey production involves the costly removal of large volumes of water. This necessarily results in a high price to the consumer, and consequently a low consumer demand. The quantities of lactose produced are unlikely to increase appreciably as there is only a limited demand for this sugar, and it is still too early to tell whether current research into alternative uses for the whey, such as the production of food yeast (Chapman, 1966), will make significant inroads into the very large whey surpluses. It is clear that the conversion of these surpluses into pigmeat is still the most profitable single outlet for a large amount of the whey produced. On the basis of calculations similar to those made by Owtram, (1961) full utilization of the whey produced in 1966 if fed alone, could yield up to 19,000 tons of pigmeat. Needless to say, under the more normal feeding systems in which 1 lb meal daily, is also fed, production levels even higher could be envisaged.