Showing papers in "Journal of Food Science in 1985"
TL;DR: In this paper, a collaborative study was conducted to develop a rapid, simple and reliable procedure for determining the solubility of food protein prod- ucts, e.g., spray-dried whey protein concentrate, sodium caseinate, egg white protein and soy protein isolate.
Abstract: A colaborative study was conducted to develop a rapid, simple and reliable procedure for determining the solubility of food protein prod- ucts, e.g., spray-dried whey protein concentrate, sodium caseinate, egg white protein and soy protein isolate. The procedure was devel- oped by modifying the nitrogen solubility index (NSI) procedure. Pro- tein content and soluble protein were determined by micro-Kjeldahl or biuret procedures with standard deviations of ? 0.83-4.12 for all proteins except caseinate which had a value of Y? 13.95. Although the biuret and micro-Kjeldahl procedures generally provided comparable accuracy and precision for protein content and solubility of certain proteins, the biuret procedure exhibited considerable error and vari- ability for other proteins. INTRODUCTION COMMERCIAL food protein products are important func- tional ingredients in a number of formulated food products (Kinsella, 1976; Pour-El, 1979; Cherry, 1981; Morr, 1982). These protein products, which are customarily spray-dried, must in most cases provide a high degree of solubility in order to be useful and functional. The solubility of these protein prod- ucts is dependent upon the physicochemical state of their pro- tein molecules, which are either favorably or adversely affected by heating, drying and other processing treatments during their manufacture and storage. Protein solubihty is commonly expressed as water-soluble nitrogen, nitrogen solubility index, water-soluble protein or protein dispersibility index (Wolf and Cowan, 1975). These latter methods utilize different dispersion media and proce- dures and different experimental conditions for recovering and quantitating the soluble proteins. These procedures are gen- erally tedious and time-consuming and are unsatisfactory for routine work. Thus, researchers commonly resort to short-cut solubility methods which frequently fail to correlate well with the physicochemical and functional properties of the protein products @hen, 1976). This collaborative study was undertaken to develop a rapid, convenient and reliable protein solubility procedure that would be suitable for characterizing large numbers of protein prod- ucts. A major objective underlying the development of this procedure was to identify and eliminate sources of variability in the
459 citations
TL;DR: In this article, different osmotic solutions, with or without low quantities of added NaCl, were tested to evaluate their effects on the characteristics of the osmosed apples (chosen in our experiences as a fruit "model").
Abstract: Different osmotic solutions, with or without low quantities of added NaCl, were tested to evaluate their effects on the characteristics of the osmosed apples (chosen in our experiences as a fruit “model”). Water loss and water activity of final product were affected not only by the aw of the osmotic agent but also by the gain of solids in the sample. At the same time of treatment, solid gain depended on chemical composition of the syrups and the shape of the samples. Addition of small quantities of NaCl to osmotic solutions increased the driving force of the drying process.
322 citations
TL;DR: In this paper, the effects of various reagents on the formation, hardness and solubility of heat-induced gels of soybean 7S, 11S globulins and isolate were studied.
Abstract: The effects of various reagents on the formation, hardness and solubility of heat-induced gels of soybean 7S, 11S globulins and isolate were studied. Gels were formed in 30 mM Tris HCl buffer (pH 8.0) with or without reagents by heating at 80°C for 30 min. The results indicated that electrostatic interactions and disulfide bonds are involved in the formation of 11S globulin gels; mostly hydrogen bonding in 7S globulin gels and hydrogen bonding and hydrophobic interactions in soy isolate gels. Analyses of the proteins solubilized from the gels indicated that the basic subunits of 11S globulin interact with 7S globulin in soy isolate gels. The contribution of certain acidic subunits to network formation in US soy isolate gels is limited
224 citations
TL;DR: Muscles from the round and chuck, excluding the infraspinatus, were generally scored lower by the sensory panel than muscles from the loin and rib, and large ranges were observed among muscles for percent fat, sarcomere length, and total collagen.
Abstract: Chemical and sensory properties of the following thirteen muscles from ten Angus steers were evaluated: semimembranosus, semitendinosus, adductor, biceps femoris, rectus femoris, gluteus medius, psoas major, longissimus - loin portion (LD-L), longissimus - rib portion (LD-R), triceps, infraspinatus, pectoral, and supraspinatus. Steaks (3.8 cm) were cooked to 70°C internally on open hearth grills for sensory evaluation. Muscles from the round and chuck, excluding the infraspinatus, were generally scored lower by the sensory panel than muscles from the loin and rib. The psoas major, LD-L, LD-R, and infraspinatus were more tender (P < 0.05) than seven other muscles; WBS values followed the same trend. Large ranges were observed among muscles for percent fat, sarcomere length, and total collagen.
193 citations
TL;DR: On the whole, roe was well balanced with the essential amino acid and had a good E/NE ratio and may be considered a food source of high-quality protein.
Abstract: Crude protein, total lipid, water, cholesterol, and amino acid com-position of the roe of eighteen Pacific marine species were determined and compared with those of muscle from the same marine species. Crude protein and total lipid were higher in roe than in muscle, while water was lower. Cholesterol in roe was generally tenfold higher than that of muscle but only around one-fourth that of hen egg yolk. Glutamic acid, leucine, and aspartic acid were generally found to be the major components of roe. Leucine and proline content were significantly greater in roe than in muscle. On the whole, roe was well balanced with the essential amino acid and had a good E/NE ratio and may be considered a food source of high-quality protein.
150 citations
TL;DR: In this paper, the physicochemical and functional properties of proteins in salt extracts from beef top round and rockfish fillet were investigated. But, the results were limited to a single protein type and were dependent on pH, freezing, species and sample variability.
Abstract: Properties of proteins in salt extracts from beef top round and rockfish fillet changed upon heating and were dependent on pH, freezing, species and sample variability. Generally, heating to >45°C, freezing or lower pH (5.5) decreased dispersibility, increased surface hydrophobicity and slightly decreased sulfhydryl content. Emulsifying and fat binding properties followed parallel trends, being improved under conditions favoring combinations of high dispersibility, hydrophobicity and sulfhydryl content (i.e., heating at <45°C, higher pH, unfrozen). However, high temperature-low pH heating improved fat binding and favored gelation, which might be explained by hydrophobic interactions. Significant (P<0.001) multiple regression models were obtained describing relationships between physicochemical and functional properties of beef and fish proteins.
146 citations
TL;DR: Rosemary oleoresin (20 ppm) was used as an antioxidant in turkey breakfast sausages prepared with 75% hand deboned turkey meat and 25% mechanically deboned Turkey meat as discussed by the authors.
Abstract: Rosemary oleoresin (20 ppm) was used as an antioxidant in turkey breakfast sausages prepared with 75% hand deboned turkey meat and 25% mechanically deboned turkey meat. It was compared to similarly formulated products with butylated hydroxyanisole/butylated hydroxytoluene (BHA/BHT, 200 ppm) and a control with no antioxidants. 2-Thiobarbituric acid-reactive substances in samples stored at 4°C demonstrated that rosemary oleoresin was comparable to a commercial blend of BHA/BHT/citric acid in suppressing lipid autoxidation. Sensory analysis was in agreement with these results. Analysis of volatile aroma compounds revealed the occurrence of oxidatively derived carbonyls in the sausages without antioxidants, while the antioxidant-treated sausages were essentially free from these carbonyls.
139 citations
TL;DR: In this article, a theoretical framework is proposed as a useful analytic tool for predicting consumer responses to novel foods based on the theory of cognitive dissonance, which postulates that the hedonic response to food is a function of the degree to which expectancies about the food are matched by subsequent experiences with it.
Abstract: Six experiments were conducted to examine factors affecting the consumer acceptance of novel foods. Variables included for analyses of their effects were: (1) preparation variables; (2) product name and type of serving vessel; (3) brand labels and packaging; (4) availability of product information; (5) nature and quantity of product information; and (6) degree of familiarity of the user with the product. Results of these experiments were interpreted within a theoretical framework that postulates that the hedonic response to food is a function of the degree to which expectancies about the food are matched by subsequent experiences with it. Based on the theory of cognitive dissonance, this theoretical framework is proposed as a useful analytic tool for predicting consumer responses to novel foods.
134 citations
TL;DR: The functional properties of glucosinolate-free canola meals were studied and compared with those of hexane-extracted canola and soybean meals as discussed by the authors, and the results showed that the crude protein content in the meal was comparable to that of soybean meal.
Abstract: The functional properties of glucosinolate-free canola meals were studied and compared with those of hexane-extracted canola and soybean meals. The glucosinolate-free meals were obtained by a two-phase solvent extraction of canola seed using 10% NH3 in methanol or in methanol containing 5% water, and hexane as the second phase. The glucosinolate content decreased to trace levels. The crude protein content in the meal was comparable to that of soybean meal. The two-phase solvent extraction process gave canola meals with lower solubility properties but with very high fat absorption compared to both the corresponding laboratory-prepared, hexane-extracted meals and commercially produced soybean meal.
129 citations
TL;DR: Toxin production by C. botulinum type E was studied in cod, whiting, and flounder filets packaged in air-permeable film, vacuum packages and packages flushed with N2 or CO2 during storage at 8°, 12° or 26°C as discussed by the authors.
Abstract: Toxin production by C. botulinum type E was studied in cod, whiting, and flounder filets packaged in air-permeable film, vacuum packages and packages flushed with N2 or CO2 during storage at 8°, 12° or 26°C. Cod and whiting filets were flushed with CO2 and stored continuously at 4°C or cycled between 4° or 8° and 26°C. Cod and whiting fillets were flushed with gas mixtures and stored at 8°C or 26°C. Flounder deteriorated rapidly and was rejected by sensory evaluation prior to toxin detection during vacuum or modified atmosphere storage at 12°C and 8°C but after toxin detection at 26°C. Toxin was present either prior to or simultaneously with sensory rejection of cod and whiting fillets for all vacuum or modified atmosphere treatments and temperature regimens.
115 citations
TL;DR: In this article, the effects of phytate and partially hydrolyzed sodium phytates on pepsin digestion of casein and bovine serum albumin were evaluated by an in vitro procedure using dialy-sates.
Abstract: The effects of sodium phytate and partially hydrolyzed sodium phytate (0 - 82% hydrolyzed) on pepsin digestion of casein and bovine serum albumin were evaluated by an in vitro procedure using dialy-sates of pepsin digestion over a period of 0 – 23 hr. The inhibitory effect of phytate differed with substrate and increased with dose level. At the highest phytate level, the digestion of casein and bovine serum albumin was reduced by 14% and 7%, respectively. The inhibitory effect of the phytate was inversely correlated with the degree of phytate hydrolysis. Hydrolysis for 16 hr almost eleminated the inhibitory effect of phytate.
TL;DR: In this paper, a method was developed for the rapid, accurate analysis of C-7 oxdized cholesterol derivatives (C-7 OCDs) in muscle and other foods.
Abstract: A method was developed for the rapid, accurate analysis of C-7 oxdized cholesterol derivatives (C-7 OCDs) in muscle and other foods. The method avoids saponification. Total lipid extracts were fractionated on silica gel columns to concentrate trace sterol oxides from triglycerides, cholesterol, and phospholipids. Sterol oxides in eluates were quantified by normal-phase high performance liquid chromatography. Recoveries of C-7 OCDs added to beef approached 100%. Pancake mix, French fries, and organ product “concentrates” sold in health food stores contained from 1 to 70 ppm of C-7 OCDs (7-keto, 7α-hydroxy and 7β-hydroxycholesterol), but none could be detected in raw beef, fried chicken, cooked hamburger, beef jerky or liver sausage.
TL;DR: In this paper, several parameters that might influence the vanillin assay for tannin analysis of dry bean (Phaseolus vulgatis L.) varieties were investigated, such as time elapsed after grinding as well as storage under high humidity conditions.
Abstract: Several parameters that might influence the vanillin assay for tannin analysis of dry bean (Phaseolus vulgatis L.) varieties were investigated. The assayable tannin content decreased with decreasing particle size of the bean flours. Time elapsed after grinding as well as storage under high humidity conditions markedly influenced tannin assays. The solubihty of tannins was dependent on the type of solvent used, with methanolic extraction requiring shorter periods as compared to extraction with acidified methanol. Color differences within the bean samples appeared to be the prime cause of variation in tannin analysis of beans. Extractions on seed coats alone increased the assayable tannin by 1.1-2.5 times compared to extractions of bean flours.
TL;DR: In this article, a 19 mm diameter split-barrel laboratory extruder was used to process wheat starch in varying conditions of barrel temperature (79 −121oC), screw speed (50, 100 rpm) and moisture content (25, 30%).
Abstract: Wheat starch was processed in a 19 mm diameter split-barrel laboratory extruder under varying conditions of barrel temperature (79–121oC), screw speed (50, 100 rpm) and moisture content (25, 30%). Final product and samples removed from along the barrel length were examined for changes in molecular size by dilute solution viscometry. Final products were also examined for paste viscosity and estimated degree of cook. A mathematical model was developed which relates the residence time of the starch in the barrel, the nominal shear stress acting on the starch and the degree of cook of the product to the extent of molecular degradation of the starch. Solution viscometry was found to be more rapid than gel permeation methods previously used to determine the extent of molecular changes.
TL;DR: Isocratic HPLC techniques were developed for the quantitative analysis of sugars in raw and baked sweet potato roots as mentioned in this paper, and over 95% recoveries of all sugars added to sweet potato root were obtained.
Abstract: Isocratic HPLC techniques were developed for the quantitative analysis of sugars in raw and baked sweet potato roots. The major sugars in raw roots: sucrose, glucose, and fructose, were quantitated with a cation exchange resin column (Aminex HPX-87C) heated to 75°C using HPLC-grade H2O as the mobile phase and refractive index detection. The major sugars in baked roots (convection oven or microwaved) were maltose, sucrose, glucose, and fructose. They were quantitated with an aminopropyl bonded phase column (Bio-Sil Amino 5S) at 21°C using a 70% CH3CN:30% H2O mobile phase and refractive index detection. Over 95% recoveries of all sugars added to sweet potato roots were obtained.
TL;DR: In this paper, the authors evaluated the drying effect on the product quality and found that freeze-dried and vacuum-dusted blueberries had higher soluble solids retention and were darker and redder than forced air or micro-convection dried berries.
Abstract: Lowbush blueberries have been processed by freeze dry, forced air, vacuum oven, and micro-convection methods to a moisture content of 16-25%. The drying effect on the product quality was evaluated. There were no significant differences in vitamin A and niacin retention except freeze dried berries had higher vitamin C retention. No significant differences occurred in retention of mineral content except higher sodium and lower magnesium were found in the micro-convection and freeze dry methods, respectively. Freeze dried and vacuum dried blueberries had higher soluble solids retention and were darker and redder than forced air or micro-convection dried berries. Freeze dried berries were found to have highest rehydration ratio and lowest bulk density.
TL;DR: The junctions between the muscle fibers and the connective tissue of blue grenadier were studied using scanning electron microscopy and it appears that the fibrils are destroyed by endogenous collagenases and/or other proteinases.
Abstract: The junctions between the muscle fibers and the connective tissue of blue grenadier (Macruronus novaezelandiae Hector) were studied using scanning electron microscopy. In fish before, during, and just after rigor mortis, the muscle fibers are attached to the myocommatal connective tissue sheets by fine collagenous fibrils. After chilled storage these fibrils deteriorate and the muscle fibers gradually detach from the myocommata. It appears that the fibrils are destroyed by endogenous collagenases and/or other proteinases.
TL;DR: Data suggest that it is likely that A. hydrophila strains associated with human gastroenteritis are capable of growing in foods at refrigeration temperatures currently considered adequate for preventing the growth of foodborne pathogens.
Abstract: Growth of clinical isolates of Aeromonas hydrophila at various temperatures, pH values, and salt levels was studied in BHI broth. A majority of the isolates grew at 4-5°C and 42°C, and all grew equally well over the range 20-35°C. At 28°C, most isolates could tolerate 4% NaCl, while at 4°C only a limited number grew in 3% NaCl. Similarly, isolates could better tolerate acidic conditions when cultured at 28°C as compared to 4°C. These data suggest that it is likely that A. hydrophila strains associated with human gastroenteritis are capable of growing in foods at refrigeration temperatures currently considered adequate for preventing the growth of foodborne pathogens.
TL;DR: In this article, the analysis of anthocyanins by a combination of droplet countercurrent chromatography, thin-layer chromatography and on-line high-performance liquid chromatography was applied to the acidified ethanol extract of cowberry (lingonberry), Vaccinium vitesidaea L, In addition, 3-galactoside (880%), 3-arabinoside, and 3-glucoside(14%) of cyanidin, delphinidin-3-glicoside was identified
Abstract: The analysis of anthocyanins by a combination of droplet counter-current chromatography, thin-layer chromatography and on-line high-performance liquid chromatography was applied to the acidified ethanol extract of cowberry (lingonberry), Vaccinium vitesidaea L, In addition to 3-galactoside (880%), 3-arabinoside (106%), and 3-glucoside (14%) of cyanidin, delphinidin-3-glucoside (less than 01%) was identified The total anthocyanin content was determined to be 174 mg/100g fresh fruit
TL;DR: In this article, conditions (pH, temperature, time) for the extraction of sugar beet pulp pectins were studied on a laboratory scale and transposed into a pilot plant, where good yields (∼ 14%) were obtained if the pulp is treated at pH 1.0, 85°C for 1 hr.
Abstract: Conditions (pH, temperature, time) for the extraction of sugar beet pulp pectins were studied on a laboratory scale and transposed into a pilot plant. Good yields (∼ 14%) of pectins are obtained if the pulp is treated at pH 1.0, 85°C for 1 hr. The characteristics of the pilot extracted pectins are very close to those of the laboratory ones, except for a lower molecular weight (∼30,000 daltons). Their physicochemical properties confirm their poor gelling ability.
TL;DR: A kinetic reaction model which accounts for the reversibility of the degradation reaction was adopted and can predict the amount of betanine remaining before and after regeneration of the pigment.
Abstract: The degradation and regeneration kinetics of betanine in solution at pH 5.0 under nitrogen and oxygen were studied at 65, 75, 85 and 90°C. HPLC was used to monitor the concentration changes of betanine and its degradation products, betalamic acid and cyclodopa-S-0-glycoside. Betanine is partially regenerated. Rate constants for the degradation reaction were calculated and the activation energies for the forward and reverse reactions were determined to be 17.6 and 0.64 Kcal/mole, respectively. The enthalpy change (ΔH) was calculated as 16.8 Kcal. The presence of betalamic acid and cyclodopa-5-0-glycoside favor regeneration of the pigment. A kinetic reaction model which accounts for the reversibility of the degradation reaction was adopted and can predict the amount of betanine remaining before and after regeneration of the pigment.
TL;DR: In this paper, the authors determined the kinetics of brown color development in model systems adjusted to the range of aw 0.90 - 0.95 and found that mild reduction of a, (i.e. to 0. 90 - 0 95) together with other factors will produce microbiologically stable products.
Abstract: Conventional food preservation methods by adjustment of water activity (aw) have adverse effects on the flavor of the finished product. Recent research showed that a mild reduction of a, (i.e. to 0.90 - 0.95) together with other factors will produce microbiologically stable products. The purpose of this work was to determine the kinetics of brown color development in model systems adjusted to the range of aw 0.90 - 0.95. From results obtained one can see the strong influence of temperature and pH and the lack of influence of aw in the rate of brown color development.
TL;DR: In this paper, the effect of conventional cooking methods and the influence of season upon proximate composition, mineral, and fatty acid profile was studied in catfish (Ictalurus punctatus, Rafinesque) fillets.
Abstract: The effect of conventional cooking methods and the influence of season upon proximate composition, mineral, and fatty acid profile was studied in catfish (Ictalurus punctatus, Rafinesque) fillets. Seasonal (August, December, and April purchased fillets) influences were minimal. As expected, fried catfish fillets had significantly altered (P ≤ 0.05) fatty acid profiles compared to the raw and baked fillets. All three cooking treatments resulted in significant differences (P ≤ 0.05) in proximate composition and in the levels of potassium, phosphorus, magnesium, and iron. The information presented would be useful for nutrient data banks when dietary intake of such items is of interest.
TL;DR: In this article, the relative sensitivity of the triangle and duo-trio tests was confirmed using a model system of salt and water stimuli, in adaptation states varied by prerinses, using an R-index procedure.
Abstract: The greater sensitivity of the‘one strong, two weak stimuli’over the‘one weak, two strong stimuli’versions of the triangle and duo-trio tests was confirmed using a model system of salt and water stimuli. The relative distinguishability of salt and water, in adaptation states varied by prerinses, was measured using an R-index procedure. The relative distinguishabilities were used as the basis for a predictive model, 'sequential sensitivity analysis', to explain the relative sensitivity of versions of the triangular and duo-trio protocols. Adaptation did not furnish a complete explanation of their relative sensitivity.
TL;DR: In this article, the temperature rate of ice formation, apparent specific heat, and enthalpy were derived and expressed in terms of solids content and temperature for a range of temperature between 20° and 40°C.
Abstract: On the basis of the principles of freezing point depression, equations for the temperature rate of ice formation, apparent specific heat, and enthalpy were derived and expressed in terms of solids content and temperature. A unique characteristic constant for each food system can be determined experimentally from the calorimetric measurements. The new equations differ only slightly with similar equationspreviously developed by Bartlett in 1944 and by Schwartzberg in 1976. Reliability and accuracy of the methods are demonstrated with literature data for meat, fish and fruit juices. Enthalpy and apparent specific heat values for a range of temperature between 20° and 40°C and solids content between 10 and 50% are presented.
TL;DR: In this article, the red color of pigmented orange fruit juice was somewhat improved by pasteurization with microwaves and addition of tartaric acid and gluthathione as mildly acidic and antioxidant agents, respectively.
Abstract: The stability of the red color of pigmented orange fruit juice was somewhat improved by pasteurization with microwaves and addition of tartaric acid and gluthathione as mildly acidic and antioxidant agents, respectively. Highest stability was obtained through the formation of complexes between anthocyanins and phenolic compounds, such as rutin and caffeic acid.
TL;DR: In this article, a technique for simultaneous determination of a wide range of angiotoxic sterols in foods produced by the oxidation of cholesterol was described, using on-column injection onto a bonded phase fused silica capillary column gave excellent separation of the oxides examined.
Abstract: A technique is described for the simultaneous determination of a wide range of angiotoxic sterols in foods produced by the oxidation of cholesterol. Gas chromatography using on-column injection onto a bonded phase fused silica capillary column gave excellent separation of the oxides examined. Combined gas chromatography- mass spectrometry was used to confirm the identities of the trimethylsilyl ether derivatives of the various sterols and 6-ketocholestanol was found to be an acceptable internal standard for determination. Analysis of powdered scrambled egg mix showed the presence of several cholesterol oxides, with cholesterol-5α,6α-epoxide, cholesterol-5β,6β-epoxide and 7-ketocholesterol predominating. Other atherogenic sterols identified included 25-hydroxycholesterol, 7α-hydroxycholesterol, 7β-hydroxycholesterol and 5α-cholestane-3β,5,6β-triol.
TL;DR: In this paper, chemical changes in Haden, Irwin, Kent, and Keitt mangos stored at 16-28°C and 85-90% RH were followed to determine the optimum storage and ripening conditions.
Abstract: Chemical changes in Haden, Irwin, Kent, and Keitt mangos stored at 16-28°C and 85-90% RH were followed to determine the optimum storage and ripening conditions. Weight loss was slightly higher at 25° and 28°C than at 16-22°C. Breakdown in acidity during ripening was slower at 16°C. Vitamin C showed two basic trends; a general decrease as in Haden, Irwin, and Keitt or a steady increase as in Kent. Total and β-carotenoids were significantly higher at 22-28°C than at 16-20°C. No significant differences were observed with respect to carbohydrate and soluble solids content. However, sucrose increased spectacularly at all temperatures contributing most to the increase in sweetness. The pattern of chemical changes were strikingly similar in all the varieties. Temperatures of 20-22°C and 85-90% RH are recommended for storage and ripening of mangos to obtain sufficiently acceptable quality attributes.
TL;DR: Polyphenol oxidase in kiwifruit was extracted and purified through (NH4)2SO4 fractionation, dialysis and chromatography on DEAE-cellulose column and showed eight bands with oxidase activity.
Abstract: Polyphenol oxidase in kiwifruit (Actinidia chinensis planch) was extracted and purified through (NH4)2SO4 fractionation, dialysis and chromatography on DEAE-cellulose column. Polyacrylamide disc-gel electrophoresis showed eight bands with oxidase activity. The molecular weight of the dominant isozyme was 25,000 as determined by gel electrophoresis. The cresolase fraction appeared in the first peak (FA1P) and catecholase in the fourth peak (FA4P) when eluted from a DEAE-cellulose column. The optimum pH of the FA4P fraction was 7.3. The Km value was 50 mM (+) catechin for FA1P and 8.7 mM for FA4P. Ascorbic acid delayed enzymic browning in kiwi fruit. The activation energy with (+) catechin as substrate was 4.0 Kcal/mole for FA1P and 7.0 Kcal/mole for FA4P.
TL;DR: In this article, four reference whey protein concentrates (WPCs) were prepared from pasteurized and nonpasteurized acid casein whey and Cheddar cheese whey using ultrafiltration/diafiltration and spray drying processes.
Abstract: Four reference whey protein concentrates (WPCs) were prepared from pasteurized and nonpasteurized acid casein whey and Cheddar cheese whey using ultrafiltration/diafiltration and spray drying processes. The WPCs exhibited comparable composition, protein solubility and PAGE and reverse phase HPLC properties. Major differences were observed in the viscosity and foaming properties of the reference WPCs as a function of pH. The WPCs generally produced higher foam expansion but lower viscosity and stability values than for liquid egg white protein. The findings were discussed in terms of the need for additional, fundamental knowledge of the physicochemical structure and reactivity of whey proteins to understand the reasons for their poor functional performance.