• Food Science of Animal Resources
• /
• v.34 no.5
• /
• pp.665-673
• /
• 2014

We compared standard culture methods as well as conventional PCR and real-time PCR for the detection of Listeria monocytogenes (L. monocytogenes) in milk, cheese, fresh-cut vegetables, and raw beef that have different levels of background microflora. No statistical differences were observed in sensitivity between the two selective media in all foods. In total, real-time PCR assay exhibited statistically excellent detection sensitivity (p<0.05) and was less time consuming and laborious as compared with standard culture methods. Conventional culture methods showed poor performance in detecting L. monocytogenes in food with high levels of background microflora, generating numerous false negative results. While the detection of L. monocytogenes in fresh cut vegetable by culture methods was hindered only by L. innocua, various background microflora, such as L. innocua, L. welshimeri, L. grayi, and Enterococcus faecalis appeared on the two selective media as presumptive positive colonies in raw beef indicating the necessity of improvement of current selective media. It appears that real-time PCR is an effective and sensitive presumptive screening tool for L. monocytogenes in various types of foods, especially foods samples with high levels of background microflora, thus complementing standard culture methodologies.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.6
• /
• pp.1152-1157
• /
• 2001

Two kinds of samples were prepared from the loin in the carcass with grade B2 and D, which were chilled for 24 hour after slaughter. The fresh beef in this study were obtained by chilling the loin for 1 day after wrapping them. On the other hand, the chilled beef were obtained by cutting the loin by 500 g and chilling them for 30 day after vacuum packing. The experiment was carried out to compare the palatability related with characteristics of loin with grade B2 and D and to investigate the chilling effect of the loin with grade D. In the case of fresh beef, it was found that the loin with grade B2 has better meat color, but lower pH, lactic acid content, and myoglobin content, than them of the loin with grade D. Also, the loin with grade B2 has lower tenderness due to its low hardness and chewiness, and high myofibrillar fragmentation index (MFI). Furthermore, it has high monounsaturated fatty acid/saturated fatty acid (MUFA/SFA) and ATP content, and good raw meat aroma. It also shows an excellent palatability of cooked meat, although it has low cooking loss and heat shotening. On the other hand, the loin with grade D has higher chilling effect on hardness, chewiness, MFI and MUFA/SFA, than them of the loin with grade B2. However, in the case of chilled beef, the loin with grade D shows much worse tenderness, cooked meat aroma, and palatability than them of the loin with grade B2.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.6
• /
• pp.829-833
• /
• 2012

To investigate the effects of oyster mushrooms (Pleurotus ostreatus) on beef and pork tenderization, freezedried mushroom (whole, cap, and stem) powder and mushroom extracts were prepared. Both fresh and boiled beef and pork had mushroom power and extract powders spread on them, and let sit for 30 minutes at room temperature. After that, the hardness and amino nitrogen content of the meats were measured. The hardness of the meat decreased by about 20%~35% after spreading. Also, the amino nitrogen contents increased due to the effect of protease in the mushrooms. The effects were greater in raw beef. The mushrooms showed almost the same effects regardless of which part of the mushrooms were used (whole, cap, and stem).

• Journal of Nutrition and Health
• /
• v.10 no.2
• /
• pp.27-34
• /
• 1977

The present study was carried out to evaluate the nutritional quality of rabbit meat protein. The composition of amino acids contained in rabbit meat was compared with those of other animal meats such as beef, pork and chicken. Also included in this study was the question whether the cooking and storage conditions affect the amino acid composition and the pepsindigestibility of rabbit meat protein. The results are summarized as follows: 1. The large variation observed from sample to sample of EAA (essential amino acid) composition in rabbit meat was found to be an interesting but peculiar property of rabbit meat protein. The most limiting amino acid of rabbit meat protein was phenylalanine, whereas methionine was the first limiting amino acid of both beef and pork proteins. Chemical scores of various meat proteins were 68, 65, 66, and 74 for rabbit meat, beef, pork, and chicken respectively. 2. In pan roasting, the EAA damaged most by heat was methionine (15%). When cooked after two months of frozen storage, lysine decreased most. 3. Higher pepsin digestibility was obtained by cooking rabbit meat after seasoned in alcohol, ginger juice, and other spices compared with various other cooking conditions without seasoning. The pepsin digestibility value was even higher for the seasoned meat than for the raw meat. 4. Among various meats tested the rabbit meat showed the lowest pepsin digestibility. 5. A simple measurement of released methionine could be used to determine relative digestibility instead of measuring $NH_2-N$ content after pepsin digestion. From all the results obtained in this study it can be concluded that rabbit meat is a good Protein food item when used fresh and stored properly to prevent rancidity problems. It is suggested to study further the peroxidation effect of unsaturated fatty acids on protein quality. This study was supported by the Ministry of Science and Technology in Korea.

• Nutrition Research and Practice
• /
• v.14 no.6
• /
• pp.637-653
• /
• 2020

BACKGROUND/OBJECTIVES: This study examined the associations between food consumption frequency of Korean adults and self-perceived chewing difficulty, using the food frequency questionnaire (FFQ, 112 items) from 2013-2016 of the Korea National Health and Nutrition Examination Survey (KNHANES). SUBJECTS/METHODS: Subjects were divided into not difficult in chewing (NDC) and difficult in chewing (DC) groups, with 24.17% being classified into DC. Males and females consumed 35 and 37 items less frequently than the other sex, respectively. Due to the remarkable gender difference in food consumption, gender-stratified one-sided survey regression analysis was performed after adjusted for the effect of age, household income, and self-rated health status. RESULTS: Thirty-four items of FFQ were significantly less consumed by the DC group. Females exclusively consumed less beverages and alcohol while males showed the same for fruits and milk·dairy products. Consumption frequency of 8 items such as steamed potatoes·grilled potatoes, stir fried beef, other kimchi·fresh vegetable kimchi, orange, sour pork·pork cutlet, tteokbokki and green tea were significant only in males. In contrast, 17 items including cooked rice with other grains and legumes, boiled egg·steamed egg, Korean cabbage kimchi, banana, and tofu stew·soft tofu stew were significant only for females. Finally, items that showed significance for both were 9 items including loaf bread, ready-to-eat cereal, steamed sweet potatoes·grilled sweet potatoes, stir-fried lotus roots·stir-fried burdock, green laver salad·brown seaweed salads, apples, tomato·cherry tomatoes, squid (raw, dried shredded, boiled, stir-fried), and curd type yogurt. CONCLUSIONS: Findings in this study suggest chewing difficulty may be an important nutritional issue that has to be dealt with for healthful food consumption, with distinct interest of gender.

• Journal of Nutrition and Health
• /
• v.12 no.2
• /
• pp.53-63
• /
• 1979

In continuation of the previous $studies^{2{\sim}3)}$, the folate activity levels in 226 Korean food items were determined by a modified microbiological assay with Lactobacillus casei. There was a large variation in folate activity between the different food groups as well as between each individual food. There was also a wide variation in the biologic availability of folate in foods and the different forms of the folate with different foods in varying amounts. Data showed that almost always, foods cooked and/or processed were lower in folate activity than fresh or raw food and the amount of the loss varied greatly in each food. In calculating dietary intake, total rather than free folate activity levels should he used. In addition, loss of folate activity during cooking and processing of foods should be considered as a major concern for appraising diets and food supplies. Among all assayed food items, including Part $I^{2)}}$ and $I^{3)}$, yeast 2800. ug total per 100g the highest folate level. Soybean, spinach, Shepherd's purse and liter of beef and pork had over 100 ug total per 100 g folate activity. Folate ranging over 50 ug total per 100 g was found in all dried legumes, nuts and seeds assayed, Garland Chrysanthemum, leek, mugwort, wafer cress, asparagus, e99 folk and beef kidney. Wheat, sweet Potatoes,dried fungus, green onion, hotrod pepper, lettuce, radish and some fermented soybeen products had considerably higher folate content ranging around 40 ug total per 100 g. Substantial amounts of folate were not found in many food groups, and among specific groups, in part in starch, sweets, fruits, meat, fish, milk, and cooked and processed foods. Soused fish, oils and fats, beverages, liquor and seasonings, other than fermented soybean products, had almost no folate.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.13 no.2
• /
• pp.65-80
• /
• 1980

Processing conditions of the krill products such as paste food, krill protein concentrate, seasoned dried krill, powdered seasoning, meat ball, and snack have been examined and the quality was evaluated chemically and organoleptically. In the processing of paste food, krill juice was yielded $71\%$ and krill scrap $29\%$. The yields of paste and broth from the krill juice showed $53\%$ and $43\%$, respectively. In amino acid composition of the krill paste, proline, glutamic acid, aspartic acid, lysine, and leucine were abundant, while histidine, methionine, tyrosine, serine and threonine were poor. The optimum condition for solvent extraction in the processing of krill protein concentrate was the 5 times repetitive extraction using isopropyl alcohol at $80^{\circ}C$ for 5 mins. The yield of krill protein concentrate when used fresh frozen materials was $10.2\%$ in isopropyl alcohol solvent and $8.8\% in ethyl alcohol, and when used preboiled frozen materials, the yield was $13.0\%$ in isopropyl alcohol and $11.8\%$ in ethyl alcohol. Amino acid composition of krill protein concentrate showed a resemblance to that of fresh frozen krill meat. In quality comparison of the seasoned dried krill, hot air dried krill was excellent as raw materials and sun dried krill was slightly inferior to hot air dried krill, but preboiled frozen krill showed the poorest quality. The result of quality evaluation for seasoning made by combination of dried powdered krill, parched powdered sesame, salt, powdered beef extract, monosodium glutamate, powdered red pepper and ground pepper showed that the hot air dried krill was good in color and sundried krill was favorable in flavor. When krill meat ball was prepared using wheat flour, monosodium glutamate and salt as side materials, the quality of the products added up to $52\%$ of krill meat was good and the difference in quality upon the results of the organoleptic test for raw materials was not recognizable between fresh frozen and preboiled frozen krill. In the experiment for determining the proper amount of materials such as dried Powdered krill, $\alpha-starch$, sweet potato starch, sugar, salt, monosodium glutamate, glycine, potassium tartarate, ammonium bicarbonate, and sodium bicarbonate in processing krill snack, sample B(containing $7.7\%$ of dried powdered krill) and sampleC (containing $10.8\%$ of dried powdered krill) showed the most palatable taste from the view point of organoleptic test. Sweet potato starch in testing side materials was good in the comparison of suitability for processing krill snack. Corn starch and kudzu starch were slightly inferior to sweet potato starch, while wheat flour was not proper for processing the snack. In the experiment on frying method, oil frying showed better effect than salt frying and the suitable range of frying temperature was $210-215^{\circ}C$.