• Preventive Nutrition and Food Science
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• v.4 no.1
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• pp.23-27
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• 1999

To evaluate the quality of fish extracts with spicy vegetables (garlic, onion and ginger) in suppressing fishy oder, fish extracts of crucian carp, loach, bastard halibut and jacopever were processed at 100 $^{\circ}C$ for 6 hours, and their in vitro and in vivo protein qualities were determined . Protein and total lipid contents were closely related to the degree of discarding floated lipid on fish extracts and the kinds of added apicy vegetables . Boiling (10$0^{\circ}C$) , appeared to improve in vitro protein qualities slightly more than hydrocooking (11$0^{\circ}C$), but those with mild processing tended to result in better protein qualities than high temperature cooking (136-14$0^{\circ}C$). Spicy vegetables did not have remarkable effects on improving in vitro protein quality parameters. Fish extracts with 10% ginger were generally higher in in vitro protein quality than with the other vegetables . In spite of higher in vivo protein digestibility of fish extracts containing spicy vegetables processed under mild conditions(10$0^{\circ}C$), PERs of those extracts were not higher htan those of extranct processed at high temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.2
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• pp.202-213
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• 1985

The protein nutritional quality of foods has become an important factor to food processors with the advent of nutritional labeling regulations for foods. Then, as is true today, the officially approved assay for protein nutritional quality was the rat based protein efficiency ratio(PER) bioassay. The PER bioassay requires a minimum of 28 days to performe, and is therefore not applicable to routine quality assurance use by the food industry. Within the past ten years there has been a research emphasis placed on the development of rapid, inexpensive, biological and/or chemical based assays for protein nutritional quality. It was hoped that if a rapid assay could be developed and thoroughly tested, it could be used in lieu of the PER bioassay in the day-to-day quality assurance screening of food ingredients and products. The rapid assays developed in the hope of attaining this goal have been based on microorganisms, proteolytic enzymes, and amino acid profiles, as well as combinations of the above. In this review, it will be described and briefly discussed many of procedures which had contributed conceptually as well as practically to the development of in vitro methods for the evaluation of protein quality. Special emphasis will be placed on the C-PER(computed protein efficiency ratio) assay which combines data from in vitro protease digestion and amino acid composition to predict protein nutritional quality designed by Satterlee et al. (1980), and the DC-PER(discriminant computed PER) which is a method of estimating protein quality based on rat assay and in vitro digestibility obtained using solely essential amino acid data will be also introduced.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1159-1165
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• 2016

The nutritional value of feed proteins and their utilization by livestock are related not only to the chemical composition but also to the structure of feed proteins, but few studies thus far have investigated the relationship between the structure of feed proteins and their solubility as well as digestibility in monogastric animals. To address this question we analyzed soybean meal, fish meal, corn distiller's dried grains with solubles, corn gluten meal, and feather meal by Fourier transform infrared (FTIR) spectroscopy to determine the protein molecular spectral band characteristics for amides I and II as well as ${\alpha}$-helices and ${\beta}$-sheets and their ratios. Protein solubility and in vitro digestibility were measured with the Kjeldahl method using 0.2% KOH solution and the pepsin-pancreatin two-step enzymatic method, respectively. We found that all measured spectral band intensities (height and area) of feed proteins were correlated with their the in vitro digestibility and solubility ($p{\leq}0.003$); moreover, the relatively quantitative amounts of ${\alpha}$-helices, random coils, and ${\alpha}$-helix to ${\beta}$-sheet ratio in protein secondary structures were positively correlated with protein in vitro digestibility and solubility ($p{\leq}0.004$). On the other hand, the percentage of ${\beta}$-sheet structures was negatively correlated with protein in vitro digestibility (p<0.001) and solubility (p = 0.002). These results demonstrate that the molecular structure characteristics of feed proteins are closely related to their in vitro digestibility at 28 h and solubility. Furthermore, the ${\alpha}$-helix-to-${\beta}$-sheet ratio can be used to predict the nutritional value of feed proteins.

• Preventive Nutrition and Food Science
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• v.3 no.3
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• pp.241-247
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• 1998

Fish extracts were processed at high temperature (136.7 ~14$0^{\circ}C$) for possible use as functional food ingredients. Raw fish meats and those hydrothermal extracts were compared with respect to in vitro and in vivo protein qualities. 95% of fat inraw meats was reduced in extracts but there were not remarkable changes in other macronutrients in freeze-dried extracts. Most of essential amino acids were decreased significantly but two times more proline and glycine were detected in extracts. High temperature cooking resulted 2.1 ~3.7 times of higher total free amino acid content infish extracts compared iwth raw meat, and taurine and glutamic acid were increased especially. Severe protein damages were occurred when invitro protein quality indices such as availblae lysine, hydrophilic browing, trypsin inhibitor formation and in vitro protein digestibility were measured on fish extracts. In vivo protein qualities were also strongly influenced by high temperature ; however rat-body-weight gain was nearly zero during PER assay, and rat PER or NPR of fish extracts were significantly lower (p<0.001) than those of cotnrol (ANRC casein) and original raw fish meats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.1
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• pp.13-22
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• 1985

A study was undertaken to evaluate the nutritional quallity of protein from precooked seafoods. Procedures for evaluation included protein efficiency ratio(PER) using the rat, computed PER(C-PER) and discriminant computed PER(DC-PER) techniques. These procedures involve the determination of in vitro digestibility and amino acid composition of the sample prior to computation of C-PER and CD-PER value in laver was higher. For the oyster, the C-PER value was very close to the PER value obtained from the rat assay. The difference between DC-PER value and rat-PER or NPR was slightly lower than that between C-PER and rat-PER except oyster and laver. Seafood samples which posses a high in vitro protein digestibility may need the DC-PER procedure could offer more advantages in predicting the protein quality of seafood samples than the DC-PER procedure which showed poor in vitro digestibility.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.257-265
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• 2011

The effects of cooking method (grilling, frying, steaming, and microwaving) on the proximate composition and protein quality of chub mackerel Scomber japonicus treated with 2, 6, and 10% sodium chloride (NaCl) brine were investigated. Moisture content decreased in all cooked samples from 60.22% in the raw sample to 48.7% in the fried samples. Brine (10% NaCl) treatment recorded the highest moisture loss. All cooked samples showed a decrease in fat content, except fried samples. Protein content increased in all cooked samples, from 47.21% in the raw sample to 63.87% in the grilled sample. Brine treatment resulted in the highest degree of fat oxidation (thiobarbituric acid-reactive substances), which was highest in the fried samples and lowest in the microwaved samples. The trypsin inhibitor (TI) concentration was highest in the microwaved samples and lowest in the fried samples. In all samples, 6% salt treatment caused the lowest TI level and the highest in vitro protein digestibility. In vitro digestibility increased from 79.4% in the raw sample to 86.43% in the fried samples. The total essential amino acids of all cooked samples increased. Results suggested that grilling and steaming had beneficial effects on the protein quality of chub mackerel.

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.165-171
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• 2003

To investigate the effect of cooking methods on protein quality of domestic fresh monkfish meat (FMM) and imported frozen monkfish meat (IMM), in vitro protein qualities were determined by amino acid anlysis, trypsin indigestible substrate (TIS) formation, and protein digestibility using the four-enzyme method. Crude protein contents of the boiled FMM and IMM were $90\%$ of the dry base, which were higher than fresh FMM $(82\%)$ and IMM $(84\%)$. Profiles of total amino acid in FMM and IMM were not changed by cooking methods. Total free amino acid contents decreased to $ 29.0-33.6\%$ for boiled $(l00^{\circ}C,\;10 min)\;and\;24\%$ for steamed $(100^{\circ}C,\;10\;min)$ samples. In vitro protein digestibilities of boiled and steamed FMM incnased $86.6-86.8\%$, compared to raw IMM $(82.9\%)$, boiled and steamed IMM $85.1-85.5\%$ and raw IMM $(83.6\%)$. TIS of FMM (23.6 mg/g solid) and IMM (15.9 mg/g solid) showed no significant (p<0.05) difference in cooking methods. The C-PERs (computed protein efficiency ratio) of boiled FMM (2.63) and IMM (2.50) were significantly higher (<0.05) than raw (1.97) and steamed FMM(1.97) and IMM(1.94). These results demonstrate that boiling of FMM and IMM improves protein digestibility and C-PER when compared to steamed FMM and IMM. Therefore, boiling could be an excellent means to maintain high-protein quality of monkfish meat. Also, the cooking method may be applicable to the preparation of monkfish stew without any loss of free amino acids.

• Food Science of Animal Resources
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• v.39 no.6
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• pp.1000-1007
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• 2019

This study investigated protein digestibility of beef puree in infant and adult in vitro digestion models. The simulated digestive juices for infant and adult were prepared. Protein digestibility of beef puree was calculated in the gastric and gastrointestinal compartments. The 10% trichloroacetic acid soluble nitrogen and α-amino group contents of gastric digesta were lower in the infant in vitro digestion model than those in the adult in vitro digestion model (p<0.05). In addition, the gastrointestinal digesta from the infant in vitro digestion model had lower value of the 10% trichloroacetic acid soluble nitrogen and α-amino group contents than those of the adult in vitro digestion model (p<0.05). The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the remarkable bands of actin and myosin light chain B were found in the digesta of beef puree from the infant in vitro digestion model. The results of this study revealed the lower protein digestibility of beef puree in infants compared to that in adults. Therefore, the development of ways to increase digestibility of meat protein can improve the nutritional quality of meat products for infants.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.741-752
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• 2020

Herein, the in vitro protein digestibility of lyophilized Protaetia brevitarsis larvae flour with and without defatting using 70% ethanol was compared with beef loin. Proximate analysis showed that the defatted larvae contained the highest protein content (p < 0.05). The viable counts of total aerobic bacteria, Escherichia coli, and coliform bacteria decreased significantly after defatting the larval samples with 70% ethanol (p < 0.05). Measurement of α-amino group content and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed higher amounts of low molecular weight proteins in the larvae compared to beef loin (p < 0.05). After in vitro digestion, the degree of protein hydrolysis of the digesta was higher for both larvae samples compared to beef loin (p < 0.05). No change was observed in the in vitro larval protein digestibility after defatting. These results highlight the excellent protein digestibility of P. brevitarsis larvae with high protein content. Defatting insect flour with 70% ethanol could enhance microbial safety while maintaining excellent protein digestibility.

• Korean journal of food and cookery science
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• v.24 no.3
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• pp.273-281
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• 2008

To determine the nutritional quality and physical properties of ginseng-chicken meat porridge, 10 kinds of ginsengchicken meat porridge samples containing waxy and/or non-waxy rice were analyzed for in vitro protein digestibility and their degree of starch hydrolysis. Viscosity and spreadness were determined for the gelatinized pastes of the porridge samples. Microphotographs of the starch granules and pastes were studied to confirm structural changes in the rice starch during cooking. The starch paste from non-waxy rice porridge had higher viscosity than the starch paste from the waxy rice porridge; however, in the case of the ginseng-chicken meat porridge, the difference in viscosity was negligible. Microphotograph comparisions between the waxy rice porridge and non-waxy rice porridge indicated apparent differences in the shapes of their starch granules and gels. The granule surface of the non-waxy rice was very rough while that of the waxy rice was very smooth; this difference would lead to organoleptical discrepancy. The added ginseng increased the protein digestibility of the chicken meat; however, the protein digestibility of the ginseng-chicken meat porridge was lower than that of the chicken meat or rice porridge due to inhibited protein digestion by the gelatinized starch. Finally, the rice porridge had increased starch hydrolysis with additions of chicken meat and vegetables.