• Title, Summary, Keyword: protein heat treatment

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Experimental and Modelling Study of the Denaturation of Milk Protein by Heat Treatment

  • Qian, Fang;Sun, Jiayue;Cao, Di;Tuo, Yanfeng;Jiang, Shujuan;Mu, Guangqing
    • Food Science of Animal Resources
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    • v.37 no.1
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    • pp.44-51
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    • 2017
  • Heat treatment of milk aims to inhibit the growth of microbes, extend the shelf-life of products and improve the quality of the products. Heat treatment also leads to denaturation of whey protein and the formation of whey protein-casein polymer, which has negative effects on milk product. Hence the milk heat treatment conditions should be controlled in milk processing. In this study, the denaturation degree of whey protein and the combination degree of whey protein and casein when undergoing heat treatment were also determined by using the Native-PAGE and SDS-PAGE analysis. The results showed that the denaturation degree of whey protein and the combination degree of whey protein with casein extended with the increase of the heat-treated temperature and time. The effects of the heat-treated temperature and heat-treated time on the denaturation degree of whey protein and on the combination degree of whey protein and casein were well described using the quadratic regression equation. The analysis strategy used in this study reveals an intuitive and effective measure of the denaturation degree of whey protein, and the changes of milk protein under different heat treatment conditions efficiently and accurately in the dairy industry. It can be of great significance for dairy product proteins following processing treatments applied for dairy product manufacturing.

Orthokinetic Stability of $\beta$-Lactoglubulin-Stabilized Emulsions : Effects of Protein Heat Treatment and Surfactant Addition

  • Hong, Soon-Taek
    • Preventive Nutrition and Food Science
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    • v.3 no.2
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    • pp.133-142
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    • 1998
  • Effects of protein heat treatment and surfactant additionoo the orthokindetic stability of $\beta$-lactoglobulin-stabilized emulsions have been investigated under turbulent flow conditions. In studies on protein-stabilized emulsions, samples which had been subjected to heat treatment(i.e. the protein solution orthe emulsion) have been found to be more prone to orthokinetic coalescene than the untreated ones. The emulsions stabilized with protein heated above the denaturation temperature(i.e. 7$0^{\circ}C$) showed the bigger initial average droplet size, which resulted in an increased orthokinetic coalescenece rate. The storage of the protein-stabilized emulsion at high temperature prior to the shearing experiment also made the emulsion less stable in the shear field. Interestingly. the addition of DATEM has been found to produce a substantial increase in orthokinetic stability of the heat-denatured protein-stabilized emulsion system, although Tween 20 is the opposite case.

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Effects of Heat Treatment on the Nutritional Quality of Milk. IV. Effects of Heat Treatment on the Physical and Nutritional Properties of Milk Protein (우유의 열처리가 우유품질과 영양가에 미치는 영향: IV. 우유의 열처리가 우유단백질의 이화학적 성질과 영양에 미치는 영향)

  • Jung, Jong-Wook;Jung, Jiyoon;Mim, Tae Sun;Oh, Sejong
    • Journal of Dairy Science and Biotechnology
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    • v.35 no.4
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    • pp.270-285
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    • 2017
  • Among milk proteins, caseins are not subjected to chemical changes during heat treatment of milk; however, whey proteins are partially denatured following heat treatment. The degree of whey protein denaturation by heat treatment is decreased in the order of high temperature short time (HTST) > low temperature long time (LTLT) > direct-ultra-high temperature (UHT) > indirect-UHT. As a result of heat treatment, several changes, including variations in milk nitrogen, interactions between beta-lactoglobulin and k-casein, variations in calcium sulfate and casein micelle size, and delay of milk coagulation by chymosin action, were observed. Lysine, an important essential amino acid found in milk, was partially inactivated during heat treatment. Therefore, the available amount of lysine decreased slightly (1~4% decrease) after heat treatment, However, the influence of heat treatment on the nutritional value of milk was negligible. Nutritional value and nitrogen balance did not differ significantly between UHT and LTLT in milk. In conclusion, our results showed that heat treatment of milk did not alter protein quality. Whey proteins denatured to a limited extent during the heat treatment process, and the nutritional value and protein quality were unaffected by heat treatment.

Effects of Milks by various Heat Treatment on Growth and Protein and Calcium Metabolism of Rats (우유의 열처리 정도가 흰쥐가 성장, 단백질 및 칼슘 대사에 미치는 영향)

  • 이정아
    • Journal of Nutrition and Health
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    • v.28 no.2
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    • pp.144-151
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    • 1995
  • This study investigates the supplementing effects of milks by various heat treatment on growth performance and protein and calcium metabolism of rats. For 4 weeks, raw, LTLT-HTST-and UHT-processed milks were given to rats which fed on a calcium free, semi-synthetic diet containing 5%casein. There were no significant differences among the experimental groups in weight gain, feed efficiency ratio and the serum level of total protein and calcium. Also, no significant differences were showed in protein efficiency, nitrogen balance, apparent protein digestibiltiy and the contents of weight and calcium of the left femur as well as 2 incisors. However, the biological value of protein in the UHT-milk group was significantly higher than that of the raw-milk group. The apparent calcium digestibility and calcium balance in the UHT-milk group were higher than those in the raw-, LTLT- and HTST-milk groups. The weight of left femur in all the groups supplemented with various heat-treated milks was significantly impair the nutritive value of protein and calcium in milk. Futhermore, UHT-processing may improve the bioavailability of protein and calcium in milk.

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A Study on the Allergenicity of Milk Protein (우유 단백질의 Allergenicity에 관한 연구)

  • 정은자
    • The Korean Journal of Food And Nutrition
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    • v.8 no.2
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    • pp.79-87
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    • 1995
  • It is generally known that the protein of talk has allergenicity and the allerenicity Induces allergic diseases. Finding methods to reduce the allergenicity of the food and develop methods to make low allergic food is the purpose of this study. For this study, 1 tried various experimental methods : heat treatment, irradation with ultraviolet and microwaves treatment with polyphosphate, enzyme hydrolysis and PCA inhibition test using guinea pigs and degrees of hydrolysis. The results obtained are as follows. Heat treatment reduced allergenicity of milk protein. The higher the heat, the better the effect. Irradiating with ultraviolet and microwave increased both the degree of protein hydrolysis and PCA inhibition reduced the allergenicity. Ultraviolet was more effective than microwaves on milk protein. Enzyme treatment increased the degree of hydrolysis and PCA inhibition, and reduced allergenicity considerably. Neutrase was more effective than alcalase on milk protein. Adding Polyphosphate did not induced protein hydrolysis, but increased PCA inhibition and reduced allergenicity.

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Protection of Canola (Low Glucosinolate Rapeseed) Meal and Seed Protein from Ruminal Degradation - Review -

  • Mustafa, A.F.;McKinnon, J.J.;Christensen, D.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.13 no.4
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    • pp.535-542
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    • 2000
  • Canola meal and seed are poor sources of ruminal undegraded protein (RUP). On average, canola meal and canola seed contains 35 and 14% RUP, respectively. Several protection methods are effective in reducing ruminal degradation of canola protein and in increasing RUP without affecting total tract protein digestibility. Heat (e.g., dry heat, moist heat and jet-sploding) and chemical (e.g., formaldehyde) treatments are the most common methods used to reduce ruminal degradability of canola protein. In most cases, heat treatments were found to be more effective than chemical treatments in protecting canola protein form ruminal degradation. Despite improvement in RUP content and intestinal availability of RUP, data form several studies showed little or no improvement in animal performance as a result of increasing the RUDP level of canola meal and seed.

Effects of Heat Treatment History of Skim Milk Powder on the Quality Characteristics of RTD Coffee with High Protein (탈지분유의 열처리 공정이 고단백질 RTD 커피의 품질 특성에 미치는 영향)

  • Ko, Bong Soo;Lee, Seok Ryong;Han, Sung Hee
    • Culinary science and hospitality research
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    • v.24 no.1
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    • pp.24-30
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    • 2018
  • This study investigated the quality of characteristics of high-protein RTD coffee using domestic and imported skim milk powder with different heat treatment. Skim milk powders (A, B) had high-heat treatment, C had medium-heat, and D and E had low-heat treatment. The transmittance of A and B were higher than that of C, and that of C were higher than that of D and E (p<0.05). The precipitate attached on bottom of container of RTD coffee using A and B were 2.993~3.053% and higher than those (0.753~0.803%) of RTD coffee using C, D and E (p<0.05), but there was no difference between those of RTD coffee using C, D and E (p<0.05). The centrifuged precipitate of RTD coffee using A and B were 1.987~2.040% and higher than those (0.820~0.830%) of RTD coffee using C, D and E (p<0.05), but there was no difference between those of RTD coffee using C, D and E (p<0.05). The proximate composition of precipitate attached on bottom of container of RTD coffee using A, which showed the highest amount of precipitate, showed 65.7% of carbohydrate, 19.0% of protein, 4.8% of fat and 4.8% of ash in dry basis, that of RTD coffee being 72.7%, 15.1%, 7.9% and 4.3% in dry basis respectively. Protein and fat content of precipitate were lower and protein and ash content were higher than those of RTD coffee. But seeing that the most increased portion was protein, precipitation of RTD coffee appears to be attributed to heat-denatured proteins.

The Soy Protein Coagulation Phenomenon by Heat-and Enzyme-Treatment

  • Park, Yang-Won;Kim, Young-Jeon
    • Preventive Nutrition and Food Science
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    • v.2 no.1
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    • pp.77-82
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    • 1997
  • The comparison soy protein coagulation by heat-and enzyme-treatment are summarized. The gelation mechanism of glycinin by heating was mainly due to dissociation and aggregation of the basic subunit of 11S globulin. In case of 7S globulin, macro-soluble aggregates may be formed by noncovalent intraction more than 30min at 8$0^{\circ}C$. Whereas, coagulum occured by the microbial enzyme was more minuter than the other Ca-, HCI-coagulum. Heat treatment attacked the basic subunit of 11S globulin and this results agreed very, how-ever, preferred acidic subunit to basic subunit of 11S globulin and attacked the 7S globulin, that could produce coagulum products within 4~5min at $65^{\circ}C$.

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The Fundamental Studies of Heat Treatment Class in Domestic Infant Formula (국산 조제분유의 열처리 등급에 관한 기초 연구)

  • 박영희
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.27 no.3
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    • pp.495-500
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    • 1998
  • To compare the extent of heat treatment in domestic infant formula, pH,titratable acidity, undenatured whey protein contents, HMF contents and protein-reducing substances of three commercial products (A, B, C) were measured. The pH of B products was lowest and the titratable acidity of B product was highest. The contents of undenatured whey protein per 100ml serum were 0∼30mg(A products), 90∼130mg(B products)and 80∼90mg(C products), respectively. Distinct differences of undenatured whey protein contents according to the manufacturer and infat's stage in age could be observed. The HMF contents of tested products showed 10.9∼21.5umol/L and B-2 product(B products for the second stage of 5∼9 month) was the highest among tested products. The protein-reducing substances showed 4.46∼9.50mg K4Fe(CN)6/100ml serum nd B-2 product was the highest among tested products.

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Studies on Heat Sensitivity of Egg Albumen III. Effects of Egg Albumen Concentration and Addition of Sugars on Heat Sensitivity of Egg Albumen (난백의 열감수성에 관한 연구 III. 난백의 농도와 당류의 첨가가 난백의 열감수성에 미치는 영향)

  • 유익종;김기성;송계원
    • Korean Journal of Poultry Science
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    • v.16 no.1
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    • pp.23-28
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    • 1989
  • This study was undertaken to find out the effect of eeg albumen concentration and addition of sugars on the functional properties of egg albumen before and after heat treatment at $60^{\circ}C$ for 5 minutes. The turbidity was decreased until 8.3% protein concentration but increased as diluted and decreased again below 3.32% protein concentration before and after the heat treatment. The foaming power was peak at 8.3% protein concentration but decreased as diluted before and after the heat treatment. The foam stability was decreased as diluted before and after the heat treatment. The turbidity was not changed by addition of sucrose before the heat treatment and decreased after the heat treatment. The foaming power was decreased by addition of over 5% sucrose before the heat treatment and decreased by addition of over 2.5% sucrose after the heat treatment . The foam stability was increased by addition of over 5% sucrose before the heat treatment and increased by addition of sucrose after the heat treatment. The turbidity was increased by addition of glucose before the heat treatment and not changed after the heat treatment. The foaming power was decreased by the addition of glucose before the heat treatment and decreased by the addition of over 5% glucose after the heat treatment. The foam stability was decreased by the addition of glucose before and after the heat treatment.

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