• Journal of Animal Science and Technology
• /
• v.65 no.6
• /
• pp.1151-1168
• /
• 2023

Tenderness and taste characteristics of meat are the key determinants of the meat choices of consumers. This review summarizes the contemporary research on the molecular mechanisms by which postmortem aging of meat improves the tenderness and taste characteristics. The fundamental mechanism by which postmortem aging improves the tenderness of meat involves the operation of the calpain system due to apoptosis, resulting in proteolytic enzyme-induced degradation of cytoskeletal myofibrillar proteins. The improvement of taste characteristics by postmortem aging is mainly explained by the increase in the content of taste-related peptides, free amino acids, and nucleotides produced by increased hydrolysis activity. This review improves our understanding of the published research on tenderness and taste characteristics of meat and provides insights to improve these attributes of meat through postmortem aging.

• Food Science of Animal Resources
• /
• v.44 no.4
• /
• pp.885-898
• /
• 2024

Ovomucin (OM), which has insoluble fractions is a viscous glycoprotein, found in egg albumin. Enzymatic hydrolysates of OM have water solubility and bioactive properties. This study investigated that the immunostimulatory effects of OM hydrolysates (OMHs) obtained by using various proteolytic enzymes (Alcalase^®, bromelain, α-chymotrypsin, Neutrase^®, pancreatin, papain, Protamax^®, and trypsin) in RAW 264.7 cells. The results showed that OMH prepared with pancreatin (OMPA) produced the highest levels of nitrite oxide in RAW 264.7 cells, through upregulation of inducible nitric oxide synthase mRNA expression. The production of pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin-6 were increased with the cytokines mRNA expression. The effect of OMPA on mitogen-activated protein kinase signaling pathway was increased the phosphorylation of p38, c-Jun NH2-terminal kinase, and extracellular signal-regulated kinase in a concentration-dependent manner. Therefore, OMPA could be used as a potential immune-stimulating agent in the functional food industry.

• Korean journal of food and cookery science
• /
• v.17 no.1
• /
• pp.65-79
• /
• 2001

The effects of ${\alpha}$-chymotrypsin and trypsin treatments on the functional properties (degree of hydrolysis, solubility, and emulsifying capacity) of the soy protein isolate prepared from Jinpum soybean milk(JS milk) which has been developed as low lipoxidase-active soybean variety in Korea and extracted from commercially defatted soybean meal milk(DSM milk). The mixing ratios of JS milk to DSM milk were adjusted to 10:0, 7:3, and 5:5, respectively. The general quality attributes(yield, pH, titrable acidity, moisture contents, crude protein contents, color, textural properties, and sensory characteristics) of soybean cheese which has been prepared with the resulting soy protein hydrolysates were evaluated. Jinpum SPI was better subjected to trypsin than ${\alpha}$-chymotrypsin hydrolyses as indicated by better solubility and emulsifying capacity of the hydrolysates. The degree of hydrolysis and solubility of Jinpum SPI were higher than the soybean isolates from DSM milk. The increased ratios of DSM milk in the mixture resulted in the reduced yields and crude protein content along with the lowered titratable acidity while the pH values and moisture contents showed the opposite trends. In color characteristics, the increased amount of DSM milk brought about the significantly lower Hunter color reflectance values of lightness of the cheese products, along with the higher redness and total color difference value(ΔE). However, the enzyme treatment alone was not enough to cause any color differences. The increased ratios of DSM milk also caused the significantly lowered textural parameters such as hardness, adhesiveness and cohesiveness of the soybean cheese. Between the enzyme treatments, the ${\alpha}$-chymotrypsin treated samples resulted in the higher hardness and cohesiveness values of the products than those from the trypsin-treated ones. In organoleptic properties of the product, the better mouthfeel and overall quality scores were obtained from the trypsin treatments as compared with those from the ${\alpha}$-chymotrypsin ones. The mixing ratios of 10:0 and 7:3 were more favored than that of 5:5 as far as mouth-feel, yellowness and overall quality of the products were concerned. On the overall, the mixing ratio of 7:3(JS milk: DSM milk) and the trypsin treatment of the mixture was recommended for better manufacturing of high-quality soybean cheese.

• Korean Journal of Food Science and Technology
• /
• v.24 no.6
• /
• pp.519-523
• /
• 1992

The patterns on the proteolysis of mussel protein using a commercial enzyme preparation were investigated. The best one among six commercial enzyme preparations for the manufacture of mussel extract was Corolase PP, based on the degree of hydrolysis (DH). When the raw mussel paste, without water addition, was adjusted to pH 6.5, added 0.1% (w/w dry basis) of Corolase PP. and reacted at $50^{\circ}C$ for four hours, it reached the maximum value of DH (79%). The precooking of raw mussel decreased the efficiency of extraction and hydrolysis of the protein, due to the inactivation of the autolytic enzymes contained in the mussel. During the course of proteolysis, major free amino acids such as glycine, alanine, glutamic acid and lysine, representing a characteristic brothy taste of mussel were replaced with free hydrophobic amino acids including valine, methionine, isoleucine, and leucine. The electrophoretic pattern and HPLC-GPC pattern of mussel protein hydrolysates during the hydrolysis were observed and also discussed.

• Korean Journal of Food Science and Technology
• /
• v.31 no.4
• /
• pp.1017-1023
• /
• 1999

Several extraction conditions of mussel were investigated for preparation of the extract as a natural shellfish seasoning. The conditions studied were extraction temperature and time, addition of sodium phosphates and citrate and hydrolysis with commercial proteolytic enzymes. The extracts were prepared by deshelling, grinding and aqueous extraction followed by centrifugation and filtration. Extraction at $90^{\circ}C$ for 40min showed the highest solids yield with less fishy and high umami taste. Among the several phosphates and citrate added, $Na_{3}PO_{4}$ and $Na_{4}P_{2}O_{7}$ at 1% level were most effective in terms of the yield and umami taste. The pH effects showed that pH 10 resulted the highest solids yield of 28% with less fishy taste. Even though the effect of enzymatic hydrolysis was not greatly different among the commercial enzymes tested, Protamex and Protease II were somewhat better than other enzymes in taste. When the mussel were extracted by the combined conditions, hydrolysis with Protamex followed by extraction at $90^{\circ}C$ for 40min with addition of $Na_{3}PO_{4}$ at pH 10, the solid yields increased up to 30% which was about 58% improvement and high intensity of umami taste and less fishy flavor.

• Journal of Animal Science and Technology
• /
• v.52 no.5
• /
• pp.435-440
• /
• 2010

Whey protein concentrate (WPC) is widely used to increase the nutritional and functional properties of food. In this study, the physiochemical and functionality of WPC-30 hydrolysates were examined to evaluate the possibility of application in the food industry. The WPC-30 was manufactured using ultrafiltration and spray-drying, and then hydrolyzed with proteolytic enzyme including alcalase, flavourzyme, nuetrase and protamex. Enzymatic hydrolysis had a significant influence on the physicochemical properties as evident from the increased foaming capacity, solubility. Alcalase caused highest protein hydrolysis (3.26%) and the bitterness. Foaming capacity was largest in WPC-30 hydrolysate treated with flavourzyme. Protein solubility at various levels of pH was highest in protamex-treated WPC-30 hydrolysate. However, the solubility of WPC-30 hydrolysates was significantly improved in alkaline condition than in acidic and neutral conditions. The study revealed that spray dried enzyme modified WPC can be used in various functional food.

• Food Engineering Progress
• /
• v.15 no.1
• /
• pp.41-47
• /
• 2011

The defatted rice bran (DRB) was enzymatically hydrolyzed using eight commercial proteases for 4hr at optimum pH and temperature. Proteolytic hydrolysates were examined in supernatant and precipitate using lowry, semimicro kjeldahl and gravimetric method using weight difference before and after enzymatic hydrolysis. In lowry and kjeldahl protein assay method, two proteases (Alcalase and Protease N) were found to be the most effective enzymes. In gravimetric method, 60.6~118.3 mg protein/g DRB was hydrolyzed after eight commercial proteases treatments. Similar to lowry and kjeldahl method, 118.3 and 107.1 mg protein/g DRB were hydrolyzed after Alcalase and Protease N treatments, respectively. When two or three effective proteases (Protamex, Alcalase and Protease N) were applied at one time to obtain synergistic effect, significant increase (P<0.05) was observed when three proteases were applied at one time (63.4 mg protein/g DRB in lowry method and 204.5 mg protein/g DRB in gravimetric method). This result suggests that Alcalase and Protease N were the most effective enzymes for proteolysis of DRB and three commercial enzymes (Protamex, Alcalase and Protease N) showed the synergistic effect on the hydrolysis of DRB.

• Food Science and Preservation
• /
• v.31 no.3
• /
• pp.444-451
• /
• 2024

This study aimed to investigate the characteristics of protein hydrolysates derived from defatted egg yolk using various proteolytic enzymes and compare the antioxidant activity of the resulting hydrolysates. The defatted egg yolk powder was subjected to enzymatic hydrolysis using four different proteases (alcalase, bromelain, flavourzyme and neutrase), and the resulting hydrolysates were evaluated for their antioxidant properties. Through analysis of available amino group contents and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it was observed that the defatted egg yolk powder treated with alcalase, flavourzyme, and neutrase for 12 h exhibited a high degree of hydrolysis value. Based on the RC₅₀ values obtained from two different antioxidant analyses, all hydrolysates showed comparable antioxidant activity, except for the alcalase hydrolysate, which demonstrated notably higher scavenging activity against hydrogen peroxide than the other hydrolysates. These findings suggest the potential of protein hydrolysates from defatted egg yolk, a by-product of lecithin extraction, as natural antioxidants.

• Journal of Animal Science and Technology
• /
• v.44 no.6
• /
• pp.801-808
• /
• 2002

Proteolytic activities of some commercial milk clotting enzymes(rennet, trypsin, pepsin, papain W-40, neutrase 1.5 and protease S) in bovine skim milk containing 0.02% $CaCl_2$ were determined by measuring DH(Degree of Hydrolysis), NPN(Non Protein Nitrogen) and by comparing patterns of SDS-PAGE(Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis). The DH of microbial enzymes(neutrase 1.5 and protease S) and trypsin in bovine skim milk were higher than those of pepsin and papain W-40. The amounts of NPN in the milk treated with trypsin and the other animal enzymes(rennet and pepsin) showed the highest and lowest degrees of proteolysis, respectively. SDS-PAGE showed that trypsin and protease S hydrolyzed $\alpha$-lactalbumin and papain W-40 hydrolyzed $\beta$-lactoglobulin slightly, while neutrase 1.5 hydrolyzed both $\alpha$-lactalbumin and $\beta$-lactoglobulin after treating for 90 min. Trypsin and protease S easily hydrolyzed ${\alpha}_s$-casein and $\beta$-casein, which were not hydrolyzed by rennet. Papain W-40 hydrolyzed $\kappa$-casein more than rennet as shown in SDS-PAGE. Based on the results of the experiments, the DH and NPN of trypsin, neutrase 1.5 and protease S were shown to be higher than those of the other enzymes. The SDS-PAGE patterns of papain W-40 and neutrase 1.5 were similar with that of rennet.

• Journal of Applied Biological Chemistry
• /
• v.59 no.4
• /
• pp.285-288
• /
• 2016

Proteolytic enzymes perform hydrolysis of the peptide bonds in the protein and most commonly use in the industry. Pseudoxanthomonas sp. WD12 and WD32 were previously isolated as protease producers from a rotten wood sample. Here, we report the secreted proteolytic enzymes. The optimum enzyme reaction temperature for the secreted crude enzyme from the strain WD12 and WD32 were $50^{\circ}C$ at pH 9.0 and $45^{\circ}C$ at pH 8.0, respectively. The enzyme activities of both strains were increased by addition of KCl, NaCl, $CaCl_2$ or $MnSO_4$, and decreased by addition of $AgNO_3$, $CuSO_4$, $FeCl_3$ or $AlCl_3$. Secreted enzymes of both strains were most strongly inhibited by addition of $FeCl_3$ or $CuSO_4$. Taken together these results, WD12 could be a candidate strain of industrial alkaline protease production.