Showing papers in "Journal of Food Science in 1982"
TL;DR: In this paper, a number of Cheddar cheese samples of different ages, pH and moisture content have been examined rheologically and electrophoretically to determine whether the progressive changes in cheese texture were related to casein proteolysis.
Abstract: A number of Cheddar cheese samples of different age, pH and moisture content have been examined rheologically and electrophoretically to determine whether the progressive changes in cheese texture were related to casein proteolysis. The force-compression curves obtained by crushing cubes of cheese between small flat plates at constant speed were different for the different cheese samples and were affected by the moisture content, pH and extent of αsl-casein proteolysis that had taken place in the cheese. These results support a model of cheese micro structure in which an extensive network involving αsl- casein molecules traverses the cheese and as the cheese ripens, chymosin cleavage of αsl-casein weakens the protein network. Such a model explains the rapid decrease in Cheddar cheese yield-force that occurs during the early stages of ripening.
447 citations
TL;DR: Reduced ascorbic acid (RAA) and Vitamin A (carotenoid) contents of six vegetables obtained from six cities in the United States at two seasons of the year were determined.
Abstract: Reduced ascorbic acid (RAA) and Vitamin A (carotenoid) contents of six vegetables obtained from six cities in the United States at two seasons of the year were determined. Mean RAA content (mg/lOOg) of cabbage was 45.2, carrots 7.8, celery 6.0, corn 6.5, onions 8.4, and tomatoes 15.3. Vitamin C in cooked cabbage was 22.1, corn 6.2, and onions 5.7 mg/100g. Mean vitamin A activity (I.U.) of car- rots was 15,228, cabbage 114, celery 133, corn 219, and tomatoes 750. In cooked cabbage and corn, vitamin A content was 89 and 217 I.U., respectively. The RAA and vitamin A content of vege- tables from the six geographical areas varied significantly. Vitamin concentrations were generally lower than tabulated values. Reten- tion of RAA in cooked cabbage was 52%; in onions, 58%; and in corn, 98%. Vitamin A retention in cooked cabbage was 82%, and in cooked corn was 98%. cities, at two different seasons. The vegetables were obtained from six different areas in the United States: West (Seattle and Denver), Midwest (St. Louis and Minneapolis), and East (Boston and Atlanta), at two different times of the year. The source of the vegetables, including the gowing area (when known), and the months they were obtained, are given in Table 1. Produce typical of that being sold in each area was shipped directly to the University of Illinois via air freight to Champaign-Urbana, IL, stored at 4"C, and pre- pared for analysis within 48 hr of shipment. Tomatoes in some cases were held at room temperature (24°C) to ripen. The times and conditions during shipping were similar to what is encountered in transport from warehouses to market outlets. Sampling procedures All vegetables were analyzed raw, and cabbage, corn and onions were also cooked and analyzed. The vegetables were trimmed, peeled if necessary, washed in deionized distilled (DD) water, and blotted dry. Approximately 15-20 kg of each vegetable were sliced (carrots, celery, onions) or cut in eighths (tomatoes, cabbage). The samples for cooking and analyses were drawn from these com- posites. Approximately 7.5-10 kg of each vegetable were cooked by the methods given below. The cooked vegetables were combined and samples drawn from the composite for nutrient assay. Corn was husked, rinsed and blotted dry, and then cut from the cob for the raw samples. Corn was cooked on the cob and the kernels removed for the cooked samples. All cutting implements used were stainless steel, and care was taken to avoid contamination with minerals. Duplicate or triplicate determinations were performed for every nutrient for each raw or cooked vegetable at each sampling period from all of the geographical areas. Cooking methods
375 citations
TL;DR: Functional and electrophoretic properties of the seed flour and a protein concentrate prepared by alkaline extraction from lupin seeds were investigated and SDS-PAGE indicated presence of 13 and 12 subunits in the Seed flour proteins and the protein concentrate.
Abstract: Functional and electrophoretic properties of the seed flour and a protein concentrate prepared by alkaline extraction from lupin seeds (Lupinus mutabilis, cultivar H-6) were investigated. SDS-PAGE indicated presence of 13 and 12 subunits in the seed flour proteins and the protein concentrate, respectively. Lupin protein concentrate had good water and oil absorption and gelation properties. Solubility of lupin proteins was minimum at a pH of 4.0 but increased rapidly beyond pH 5.0. Foaming capacity of the protein concentrate could be improved by increasing concentration as well as by adding NaCl and was influenced by pH and incorporation of certain carbohydrates. Emulsion properties of lupin proteins were concentration and pH dependent. Moist heat improved the in vitro digestibility of the seed proteins. The seed flour as well as the protein concentrate did not have detectable trypsin, chymotrypsin, and α-amylase inhibitory activities.
370 citations
TL;DR: In this article, the authors compared raw and heat-processed winged bean flour with those of raw soy flour, both as a function of pH and NaCl concn.
Abstract: N solubility, emulsification capacity, foam capacity, fat and water absorption capacity of raw and heat-processed winged bean flour were compared with those of raw soy flour, both as a function of pH and NaCl concn. N solubility vs. pH profile showed only one min. at pH 4.5. Heat processing of winged bean flour lowered N solubility. Water and fat absorption capacity of winged bean flour were 2.1 and 1.4 g/g, resp.; those of raw soy flour were 3.1 and 1.2. Heat processing increased water and fat absorption capacity of winged bean flour by 38 and 57%, resp. Emulsification capacity of raw winged bean flour was higher than that of raw soy flour by about 30-60% depending on the pH. Heat processing diminished emulsification and foam capacity of winged bean flour by about 35 and 18%, resp. Incorporation of NaCl up to 0.4M improved emulsification capacity of winged bean flour and foam capacity up to 0.2M .
341 citations
TL;DR: In this paper, two inexperienced sensory panelists rated a series of ground beef samples four or six times for intensity of oxidized flavor and found that the initial range of oxidised flavor detection for this panel group was within a range of TBA numbers that closely resembled the previously determined threshold level for trained panelists.
Abstract: Fifty-two inexperienced sensory panelists rated a series of ground beef samples four or six times for intensity of oxidized flavor. Correlation coefficients for sensory scores versus TBA numbers were significant but low. Variability in panelist scoring appeared to account partly for the lower values. Of the 52 panelists tested, 28 were determined statistically to be consistent in their scoring of the treatment variables. Correlation coefficients were higher for this group of panelists. The initial range of oxidized flavor detection for this panel group was within a range of TBA numbers that closely resembled the previously determined threshold level for trained panelists.
327 citations
TL;DR: The colorimetric assay using m-hydroxydiphenyl for analysis of uronic acids is used to measure pectins in plant materials because of its relative insensitivity to the presence of nonuronide carbohydrates as mentioned in this paper.
Abstract: The colorimetric assay using m-hydroxydiphenyl for analysis of uronic acids is used to measure pectins in plant materials because of its relative insensitivity to the presence of nonuronide carbohydrates. Still, large amounts of these carbohydrates are often associated with pectins and it has been found that levels may be present which can interfere with this analysis. Concentrations of 5 nonuronide carbohydrates commonly associated with pectins were used to simulate and study this interference and recommendations are made to increase the accuracy of this method when high levels of these substances are present. The corrections suggested are appropriate for final sample dilutions that contain more than 200 μg/ml of nonuronide carbohydrate material.
273 citations
TL;DR: A protein concentrate (71.45% protein on a dry weight basis) was prepared from winged bean [Psophocarpus tetragonolobus (L.) DC] seeds as mentioned in this paper.
Abstract: A protein concentrate (71.45% protein on a dry weight basis) was prepared from winged bean [Psophocarpus tetragonolobus (L.) DC] seeds. Solubility of the protein concentrate was minimal at a pH of 4.0. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the bean flour proteins and protein concentrate indicated 9 subunits each, with apparent molecular weight ranges of 27,000–380,000 and 14,200–143,000 daltons, respectively. Least gelation concentrations and water and oil absorption capacities of the seed flour and the protein concentrate were determined. Emulsion and foaming properties of the protein concentrate were investigated. Effect of moist heat on seed protein digestibility was assessed in vitro. Protein concentrate had lower tannins and trypsin, chymotrypsin, and α-amylase inhibitory activities compared to bean flour.
272 citations
TL;DR: In this article, the effects of dehulling on phytic acid; trypsin, chymotrypsin and α-amylase inhibitory activities; and tannins of ten cultivars of dry beans (Phaseolus vulgaris L.) were investigated.
Abstract: Effects of dehulling on phytic acid; trypsin, chymotrypsin, and α-amylase inhibitory activities; and tannins of ten cultivars of dry beans (Phaseolus vulgaris L.) were investigated. Phytic acid content of whole beans ranged from 1.16-2.93%. Dehulling significantly increased the phytic acid content of beans (range 1.63-3.67%). Dehulling also increased trypsin, chymotrypsin, and α-amylase inhibitory activities of the beans. Tannin contents of whole and dehulled beans ranged from 33.7-282.8 and 10.0-28.7 me. catechin equivalent/100g beans, respectively. Removal of seed coats lowered the tannin content of beans by 68–95%. Tannins were not detected in white seeded cultivars of Sanilac, Great Northern, and Small White. Dehulling significantly improved the in vitro digestibility of bean proteins.
253 citations
TL;DR: In this article, a method for determining the nonheme iron content of meats was evaluated and used to determine the non-heme and heme-iron content of selected muscles from beef, pork, and lamb.
Abstract: A method for determining the nonheme iron content of meats was evaluated and used to determine the nonheme and heme iron content of selected muscles from beef, pork, and lamb. The method allows a quantitative determination of nonheme iron in meat and is influenced to only a minor degree by the presence of heme iron. Heating meat in a boiling water bath increased the nonheme iron content of the meat. Possibly, heating accelerates oxidative cleavage of the prophyrin ring thereby allowing release of the iron from the heme complex. Total iron content differed between muscles in pork and beef but not in lamb. Heme iron, expressed as percent of the total iron, in raw pork, lamb, and beef average 49, 57, and 62%, respectively.
206 citations
TL;DR: Amylase inhibitor activity (AIA) of chickpea extracts was investigated and showed higher inhibitor activity towards pancreatic amylase than salivary amylases, though clear-cut differences were not observed among- the cultivars.
Abstract: Amylase inhibitor activity (AIA) of chickpea extracts was investigated
usmg pancreatic and salivary amylases. The extracts showed
higher inhibitor activity towards pancreatic amylase than salivary
amylase..Mean values indicated slightly higher inhibitory activity in
desi than kabuli cultivars, though clear-cut differences were..not
observed among- the cultivars. While in vitro starch digestibility of
meal samples indicated no large differences among desi and kabuli
types of chickpea, the mean values of digestibility of- isolated
starches of kabuli -types wasp higher than those -of desi types: The
mean values of stachyose were higher in desi cultivars. When desi
and kabuli types were considered together, stachyose- and raffmose
contents were not found significantly related to the concentrations
of total soluble sugars while stachyose showed a significant correlation
with raftinose.
190 citations
TL;DR: In this paper, several established methods of phytic acid determination in soybeans were evaluated and three assay methods relying on phosphorus analysis were compared, based upon good agreement with anion-exchange column results and acceptable reproducibility, the best methods were (1) precipitate analysis of phosphorus after extraction with 3% TCA + 10% sodium sulfate, or (2) supernatant difference method after extracting with 1.2% HCl.
Abstract: Several established methods of phytic acid determination in soybeans were evaluated. Iron analysis methods, which rely on a 4:6 molar ratio of Fe:P, were eliminated because this ratio was not dependable. Three assay methods relying on phosphorus analysis were then compared. The anion-exchange method was considered most accurate but not convenient for routine analysis. Analysis of the ferric phytate precipitate and a new method, analysis of the supernatant before and after ferric chloride precipitation, were judged against the anion-exchange method under different extraction conditions. Based upon good agreement with anion-exchange column results and acceptable reproducibility, the best methods were (1) precipitate analysis of phosphorus after extraction with 3% TCA + 10% sodium sulfate, or (2) the supernatant difference method after extraction with 1.2% HCl.
TL;DR: In this article, the use of cellulose-like biopolymers as functional additives for potential application in food formulations was studied, including water binding, fat binding and emulsifying properties.
Abstract: Chitin (poly-β (1⇒4)-N-acetyl-D-glucosamine), chitosan (deacetylated chitin) and microcrystalline chitin (redispersible chitin powder) were compared with microcrystalline cellulose to examine the use of those cellulose-like biopolymers as functional additives for potential application in food formulations. Water binding, fat binding and emulsifying properties were studied. Baking tests were performed with 0.5–2.0% (flour basis) of microcrystalline chitin added to wheat flour bread or to potato protein fortified (8% potato protein concentrate) white bread. Water-binding capacity and fat binding capacity of chitin, chitosan and microcrystalline chitin ranged from 230–440s (w/w) and from 170–315% (w/w). Chitosan and chitin did not produce emulsions but microcrystalline chitin showed good emulsifying properties and was superior to microcrystalline cellulose. Increasing concentration of microcrystalline chitin (0.12–0.8 g/100 ml water) had a positive effect on emulsion stability. Addition of microcrystalline chitin increased specific loaf volume of white bread and protein fortified breads. Water addition of 65% (flour basis) was found to be optimum for “chitin breads.”
TL;DR: The effects of reconstituted skim milk, and the same fermented by Lactobacillus acidophilus, were tested in rats as discussed by the authors, and the results showed that rats receiving the fermented milk had lower (P < 0.05) serum cholesterol levels (65 mg/dl) than did the water-fed or milk-fed rats.
Abstract: The effects of reconstituted skim milk, and the same fermented by Lactobacillus acidophilus, were tested in rats. Rats were fed a stock diet and drinking water containing one of three milk treatments: (1) no supplementary milk; (2) 10% milk; or (3) 10% milk fermented by L. acidophilus. After 4 wk, rats receiving the fermented milk had lower (P < 0.05) serum cholesterol levels (65 mg/dl) than did the water-fed (78 mg/dl) or milk-fed (79 mg/dl) rats. Weight gain, feed intake, liver lipid contents and fecal lactobacilli counts were not different among treatment groups. Data indicate that factors influencing serum cholesterol levels were produced during fermentation of the milk.
TL;DR: In this article, the effect of color on the perception of sweetness and redness in five red colored solutions containing 0.25-5.0% FD&C Red 40 were quantified using magnitude estimation.
Abstract: Perceived sweetness and redness in five red colored solutions containing 0.25–5.0% FD&C Red 40 were quantified using magnitude estimation. Three panels of 14 subjects each evaluated solutions containing five sucrose concentrations ranging from 2.7–5.3%. Color had a statistically significant effect (p≤0.05) on sweetness perception in 80% of the treatments. Sweetness in darker colored solutions was 2–10% greater than the lighter reference when the actual sucrose concentration was 1% less. Sweetness increased linearly over all sucrose concentrations and over a narrow range of color intensities. Color was measured using the Gardner XL-23 Colorimeter and the G.E. Recording Spectrophotometer. All color measurements were converted to L*, a*, b* and the value arctan (a*/b*) - used to represent color intensity. The perception of increasing color intensity was a linear power law function of arctan (a*/b*).
TL;DR: The authors showed that IAA (indoleacetic acid) oxidase activity was observed in both soluble and bound fractions and paralleled the peroxidase activity in tomato fruit development, reaching a maximum at the mature green stage.
Abstract: Soluble peroxidase activity increased dramatically during the early stages of tomato fruit development, reaching a maximum at the mature-green stage. Ionically and covalently bound peroxidases were also observed, and the activities of these fractions increased steadily throughout fruit development. IAA (indoleacetic acid) oxidase activity was observed in both soluble and bound fractions and paralleled the peroxidase activity. Tissue homogenates from juvenile fruit caused an extended induction period in IAA oxidation reactions catalyzed by the purified tomato fruit peroxidase, suggesting the occurence of a high concentration of phenolic-type auxin protectors in this tissue. As the fruit developed, tissue homogenates showed a reduction in the amount of auxin protectors as the IAA oxidizing capacity of the fruit increased.
TL;DR: Optimal temperature, lower temperature limit, extent, and rate of histamine production in a tuna fish infusion broth (TFIB) varied for the strains of Proteus morganii, Klebsiella pneumoniae, Hafnia alvei, Citrobacter freundii, and Escherichia coli studied.
Abstract: Optimal temperature, lower temperature limit, extent, and rate of histamine production in a tuna fish infusion broth (TFIB) varied for the strains of Proteus morganii, Klebsiella pneumoniae, Hafnia alvei, Citrobacter freundii, and Escherichia coli studied. P. morganii and K. pneumoniae produced large quantities of histamine in a relatively short incubation period ( 2500 nmoles/ml) only at 30°C and 37°C on prolonged incubation (≥48 hr). At 72 hr of incubation, optimal temperature for histamine production was 37°C for E. coli and C freundii; 30°C for P. morganii strain 110SC2, K. pneumoniae, and H. alvei; and 15°C for P. morganii strain JM. The lower temperature limits for production of toxicologically significant levels of histamine in TFIB were 7°C for K. pneumoniae; 15°C for both P. morganii strains; and 30°C for H. alvei, C. freundii, and E. coli.
TL;DR: The relationship of marbling level and cooking to cholesterol content of beef longissimus muscle steaks was studied in this paper, which showed that raw steaks with "practically benign" marbling contained significantly less cholesterol (wet basis) than did raw Steaks with any of the other seven marbling scores.
Abstract: The relationships of marbling level (eight levels from “Moderately Abundant” to “Practically Devoid”) and cooking to cholesterol content of beef longissimus muscle steaks were studied. Only raw steaks with “Practically Devoid” marbling contained significantly less cholesterol (wet basis) than did raw steaks with any of the other seven marbling scores. However, steaks cooked to an internal temperature of 60° or 75°C showed no significant differences in cholesterol content among any of the eight marbling groups. The cholesterol content of cooked steaks was 22–48% higher than that of raw steaks when cooked to 60°C and 38–65% higher when cooked to 75°C; cooking reduced the weight of each steak, thereby increasing the cholesterol content of the steak expressed as a percentage of the cooked weight.
TL;DR: Banana (Musa sp.) starch was isolated after steeping in 0.05N sodium hydroxide as discussed by the authors, and the starch had a granule size of 20-60μ, a gelatinization temperature range of 74-83°C, and a B-type X-ray diffraction pattern.
Abstract: Banana (Musa sp.) starch was isolated after steeping in 0.05N sodium hydroxide. The starch had a granule size of 20–60μ, a gelatinization temperature range of 74–83°C, and a B-type X-ray diffraction pattern. The Brabender viscoamylogram and the swelling pattern indicated a fairly restricted-swelling starch. The starch had low iodine affinity (ca 3.30%) and contained diesterified phosphate. During ripening, the amount of starch converted into reducing sugars and sucrose increased with degree of ripeness. Small granules were converted more rapidly than large granules. Other physical and chemical properties remained similar throughout ripening.
TL;DR: In this paper, a new method for the production of fish mince from a small fatty fish is presented, which involves cutting the fish into short pieces, washing out the depot fat, dark pigments and viscera under acid (pH 4) or neutral conditions, and bone separation.
Abstract: A new method for the production of fish mince from a small fatty fish is presented. The method involves (a) cutting the fish into short pieces, (b) washing out the depot fat, dark pigments and viscera under acid (pH 4) or neutral conditions, and (c) bone separation. The resulting mince has a white appearance and a low fat content (approximately 7% of dry wt). The water-holding capacity of the acid mince is low, whereas neutral minces have values corresponding to cod mince. The fish oil can easily be recovered. Characterization of the lipids in capelin mince is presented.
TL;DR: Egusi (Colocynthis citrullus L.) kernels contain 52.0% oil, 28.4% protein (60% in defatted flour), 2.7% fiber, 3.6% ash, and 8.2% carbohydrate as discussed by the authors.
Abstract: Egusi (Colocynthis citrullus L.) kernels contain 52.0% oil, 28.4% protein (60% in defatted flour), 2.7% fiber, 3.6% ash, and 8.2% carbohydrate. They are good sources of essential amino acids, especially arginine, tryptophan and methionine, vitamins B1, B2, and niacin, and S, Ca, Mg, Mn, K, P, Fe, and Zn. The oil contains mostly oleic (15.9%) and linoleic (62.8%) acids. Protein isolates that differ in gel electrophoretic patterns and amino acid content can be prepared from the flour in one- or two-step water and sodium hydroxide extractions. The water and oil holding capacities of the flour are 0.7 and 2.6 ml/g, respectively. Thick (mayonnaise-type) emulsions form in the alkaline pH range and a stable foam forms at pH 5.0. Nutritionally, lysine is the most limiting amino acid (chemical score, 52.4).
TL;DR: The validity of the physical model on which the Hailwood and Horrobin (Trans. Far. Soc. 42B: 84; 1946) isotherm equation was developed was investigated in this article.
Abstract: The validity of the physical model on which the Hailwood and Horrobin (Trans. Far. Soc. 42B: 84; 1946) isotherm equation was developed was investigated. The results indicate that although the equation may fit sorption data for almost any type of food, it satisfies thermodynamic requirements (i.e. prediction of the temperature dependence) only for proteins and starchy foods. The results also show that plotting enthalpic changes against entropic changes for water sorption satisfies the enthalpy/entropy compensation phenomenon.
TL;DR: In this article, the microstructure of blood plasma gels was evaluated by scanning electron microscopy (SEM) and the relationship between gel structure, texture, and water binding properties of gels prepared under various conditions such as different heating temperatures, pH and protein and salt concentrations were investigated.
Abstract: Heat induced denaturation and aggregation of plasma protein solutions were studied by low shear viscometry and turbidity measurements. The microstructure of blood plasma gels was evaluated by scanning electron microscopy (SEM). Relationships between gel structure, texture, and waterbinding properties of blood plasma gels prepared under various conditions such as different heating temperatures, pH and protein and salt concentrations were investigated. Generally, it was found that the degree of elasticity and waterbinding properties decreased with an increasing degree of random aggregation of the protein gel network. The degree of aggregation increased with increasing protein and salt concentration and decreasing pH from 9 to 6. With increasing heating temperature from 77° C to 92° C, a partial disruption of the gel structure due to local aggregation phenomena was demonstrated by SEM micrographs.
TL;DR: Nine species and biotypes which contained starch were pin milled and air-classified into protein-rich and starch-rich fractions, the protein fractions were 40–90% higher than the flours in α-galactosides, especially raffinose, manninotriose, stachyose and verbascose.
Abstract: Oligosaccharide compositions of flours from dehulled seeds of eleven legumes were determined by gas-liquid chromatography and mass spectroscopy. While soybean contained 11.7% sugars, concentrations in lupine, cowpea, chickpea and lentil were about 8%; lima, navy and northern beans, field pea, mung bean and fababean contained about 5% of sugars. Sucrose represented 20–55% of the total sugars; stachyose was the principal α-galactoside in most species. In addition, high amounts of manninotriose were found in chickpea and lentil flours whereas verbascose was a major component in field pea, mung bean and fababean flours. The nine species and biotypes which contained starch were pin milled and air-classified into protein-rich and starch-rich fractions. The protein fractions were 40–90% higher than the flours in α-galactosides, especially raffinose, manninotriose, stachyose and verbascose. The starch fractions were depleted in α-galactosides, the concentrations varied from 1.2–2.8% of the fraction.
TL;DR: In this paper, a comparison was made between the amount of browning and protein quality loss during storage of whey powder under steady state conditions (25, 35 and 45°C) and a fluctuating temperature condition of 25/45°C with alternating 5 day periods at each temperature.
Abstract: Comparison was made between the amount of browning and protein quality loss during storage of whey powder under steady state conditions (25, 35 and 45°C and aw's of 0.33, 0.44 and 0.65 at each temperature) and a fluctuating temperature condition of 25/45°C with alternating 5 day periods at each temperature. The results showed that the maximum rate of browning and loss of protein quality (e-DNP-lysine and RNV by Tetrahymena assay) occured at aw 0.44 rather than at a higher aw as is found for many dried foods. The Q10's for the reactions were about 5 and 3.7 respectively, for browning and protein quality loss. Of major importance was that storage losses at constant aw, but under the fluctuating temperature condition, were significantly greater than at the mean temperature of 35°C. Using steady state data from the 25, 35 and 45°C conditions, the prediction of browning and protein quality losses for the fluctuating condition compared favorably (+ 10%) to actual losses, based on the simple Arrhenius relationship which indicates that temperature history does not significantly change reaction mechanisms.
TL;DR: In this paper, the effects of four endpoint chopping temperatures (10, 16, 22 and 28°C) on the ultrastructure of meat emulsions with a grind-mix-emulsify production system were evaluated.
Abstract: A standard frankfurter formulation (25% fat) was used to evaluate the effects of four endpoint chopping temperatures (10, 16, 22 and 28°C) on the ultrastructure of meat emulsions with a grind-mix-emulsify production system. Scanning electron microscopy (SEM) was used to evaluate the changes that occur in the ultrastructure of a meat emulsion. Thermally processed frankfurters from each of the four endpoint chopping temperature treatments were fractured, fixed, dehydrated, critical point dried, and coated with Au/Pd before SEM micrographs were taken. Micrographs suggest that maximal emulsion stability is attained as a tradeoff between two different functions. The first function is related to the interfacial protein film thickness and the second function is related to the integrity and density of the surrounding emulsion matrix, and its ability to retain that integrity during thermal processing. These two functions appear to be directly related to the fat-holding and water-binding abilities of the meat emulsion or batter.
TL;DR: The concentrations of trypsin inhibitor, hemagglutinating activity and phytic acid in the protein fractions were up to 300% higher than the original flour while saponins and dietary fiber also tended to segregate with the protein.
Abstract: Pin milting and air classification of starchy legumes enriched the protein content of the light fraction to 49–75%, within the range of defatted soybean flours and protein concentrates. The levels of trypsin inhibitors, hemagglutinating activity, saponin, phytic acid and fiber were high in navy bean flour and the levels in the protein fractions of navy and northern beans greatly exceeded those of soybean flour. Potential nutritional problems in the air-classified protein fractions of other legume species include trypsin inhibitor in lima bean and chickpea and saponin in lima bean, cowpea and lentil. Fababean and mung bean flours and protein fractions were comparatively lower in each antinutritive factor but fababean products contained vicine and convicine.
SUMMARY
THE EFFECTIVENESS of the pin milling and air classification of starchy legumes in the separation of protein and starch fractions has been amply demonstrated (Sosulski and Youngs, 1979). A previous study showed that the protein fractions also contained higher levels of oligosaccharides than the original flours while the starch fractions were depleted in sugars. In the present investigation, the concentrations of trypsin inhibitor, hemagglutinating activity and phytic acid in the protein fractions were up to 300% higher than the original flour while saponins and dietary fiber also tended to segregate with the protein. The starch fractions from most of the nine legume species and biotypes were substantially detoxified by the dry milling process. The protein fractions of navy and northern beans contained particularly high levels of essentially all of the antinutritive fractions and may require extensive processing if food uses of the products are anticipated. On the other hand, mung bean and fababean products were much lower than soybean flour in most antinutritive factors although the fababean protein fraction was enriched in vicine and convicine.
TL;DR: In this paper, model system interactions between five different legume starches (azuki red bean, split yellow pea, small red beans, bush bean, and California kidney bean), potato starch, amylose, and amylopectin and two phenolic compounds - tannic acid and catechin - were investigated.
Abstract: Model system interactions between five different legume starches (azuki red bean, split yellow pea, small red bean, bush bean, and California kidney bean), potato starch, amylose, and amylopectin and two phenolic compounds - tannic acid and catechin - were investigated. The amounts of tannic acid and catechin associated with different starches and starch fractions at room temperature (21°C) ranged, respectively, from 261-652 and 123-586 Mg catechin equivalents/100 mg starch. Heating the systems at 95°C for 30 min decreased the quantities of tannic acid and catechin associated with different starches (151-417 and 147-378 μg catechin equivalents/100 mg starch of tannic acid and catechin, respectively). Bound tannic acid and catechin decreased the in vitro digestibility of the starches.
TL;DR: Data suggest that MgCl2 would not be a satisfactory substitute for NaCl in these formulations; however, replacing 35% of the NaCl with KCl may be possible and this same replacement with LiCl was not detrimental to flavor in pork/beef formulations.
Abstract: Triplicate 4.5 kg batches of frankfurters formulated with either pork/beef or mechanically deboned turkey (MDT) were made to replace all (100%) or part (35%) of the sodium chloride (NaCl) with either potassium chloride (KCl), magnesium chloride (MgCl2) or lithium chloride (LiCl). Regardless of storage period or formulation, replacing all of the NaCl with either KCl or MgCl2 was detrimental to flavor. This same replacement with LiCl was not detrimental to flavor in pork/beef formulations. Data suggest that MgCl2 would not be a satisfactory substitute for NaCl in these formulations; however, replacing 35% of the NaCl with KCl may be possible. Because of its toxicity, LiCl is not GRAS-approved and we do not recommend its use but, its use in this study more closely approximated the sensory properties of NaCl than either KCl or MgCl2.
TL;DR: In this article, the firmness of a number of fruits and vegetables was measured by deformation, extrusion and puncture tests over the temperature range 0-45°C.
Abstract: The firmness of a number of fruits and vegetables was measured by deformation, extrusion and puncture tests over the temperature range 0-45°C. Most commodities showed decreasing firmness with increasing temperature but there were several exceptions to this general rule. For the majority of the commodities tested the firmness-temperature relationship was approximately linear. The firmness-temperature coefficient is defined as [(firmness at T2– firmness at T1)/(firmness at T1 (T2− T1)] × 100 (percent change in firmness per degree temperature change) where T1= lowest temperature and T2= highest temperature at which firmness is measured. The firmness-temperature coefficient ranged from -1.65 for apricot to +0.12 for carrot using the puncture principle, from −0.97 for Baby Gold peach to +7.7 for large Canoga strawberries tested between 30–45°C using the deformation principle, and from -0.04 for Golden Delicious apple stored 7 months to −1.34 for NK199 sweet corn using the extrusion principle.
TL;DR: In this paper, the authors investigated the thermal association-dissociation behavior of soybean 11S globulin by sucrose density gradient centrifugation and polyacrylamide gel electrophoresis.
Abstract: Thermal association-dissociation behavior of soybean 11S globulin was investigated by sucrose density gradient centrifugation and polyacrylamide gel electrophoresis. Soluble aggregates with a molecular weight of 8 × 106 were formed when 0.5% and 5% protein solutions were heated for 1 min at 100°C. At the lower protein concentration, subsequent heating caused disappearance of the soluble aggregate followed by complete dissociation into acidic and basic subunits. At the higher concentration, however, subsequent heating caused formation of highly polymerized aggregates, and gel was formed after 5 min of heating. The soluble aggregates appear to be transient intermediates in the course of gel formation of 11S globulin.