• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.148-153
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• 2006

Effects of ${\alpha}$-chymotrypsin modification on degree of hydrolysis (DH), solubility, emulsifying capacity and thermal aggregation of laboratory-purified soy protein isolate (SPI) using a lipoxygenase-defected soybean (Jinpum-kong) and commercial soy protein isolate (Supro 500E) were compared. SPIs were hydrolyzed by ${\alpha}$-chymotrypsin at pH 7.8 and $37^{\circ}C$ for 30 min. DHs of Supro 500E and Jinpum-kong SPI were increased by ${\alpha}$-chymotrypsin modification, and DH of Supro 500E was higher than that of Jinpum-kong SPI. DH of ${\alpha}$-chymotrypsin treated Jinpum-kong SPI was similar with untreated Supro 500E and DH of treated Supro 500E was the highest. Solubility, emulsifying capacity and thermal aggregation of SPIs were increased by ${\alpha}$-chymotrypsin modification, and these changes were highly related to changes in DH. Functional properties of Supro 500E were higher than Jinpum-kong SPI in both of untreated and ${\alpha}$-chymotrypsin treated SPIs.

• Journal of the Korean Chemical Society
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• v.21 no.6
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• pp.445-448
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• 1977

This study was carried out to understand the activity of ${\alpha}$-chymotrypsin, a proteolytic enzyme, to a oligopeptide in the presence of various coloring food additives. 1. The melting point of synthetic oligopeptide, Asp-Arg-Val-Tyr-Ile-His-Pro-D-Ala, ((8-D-Ala) angiotensin Ⅱ) was 210∼$212^{\circ}C$. Chemical formula and molecular weight were $C_{44}H_{67}N_{13}O_{12}{\cdot}2CH_3COOH{\cdot}H_2O$ and 970.08, respectively. 2.The amino acid rations by acid hydrolysis were Asp : 1.01, Arg : 1.03, Val : 1.00, Tyr :40.94, Ile : 1.00, His : 1.05, Pro : 1.04, D-Ala : 1.03. 3. ${\alpha}$-Chymotrypsin cleaved the oligopeptide bond between tyrosine and isoleucine (Tyr-Ile). 4. The addition of food coloring additives as determined by paper chromatogram, did not influence the inhibitory activity of ${\alpha}$-chymotrypsin on oligopeptide, (8-D-Ala) angiotensin II.

• Journal of the Korean Home Economics Association
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• v.19 no.2
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• pp.183-188
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• 1981

This study was conducted to investigate the effects of synthetic antioxidants con the degradation of angiotensin II which is made up of 8 amino acids: Asp-Arg-Val-Try-Ile-Gly-Pro-Phe, by the $\alpha$-chymotrypsin and trypsin. the results obtained were as follow; 1. Dibutyl hydroxytoluene, butyl hydroxyanisole and sodium L-ascorbate showed no inhibitory effect on the activity of $\alpha$-chymotrypsin on the angiotensin II, but ethyl protocathechuate inhibited. its activity at the concentration of 100ppm. However, the angiotension II was gradually degradated by $\alpha$-chymotrypsin after one hour incubation with ethylprotecathechuate. 2. Butyl hydroxyanisole inhibited trypsin activities above 100ppm, but no inhibitory activities was observed by the other antioxidants used in this experiment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.282-292
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• 1987

In order to exploit a new type of food source, enzamatically modified hydrolysates and the plasteins synthesized from the filefish (Nevoden modestus) protein hydrolysates by plastein reaction were investigated. The optimum conditions for enzymatic hydrolysis of filefish muscle and synthesis of plasteins using papain, pepsin, $\alpha-chymotrypsin$ and protease (from Streptomyces griceus) were determined. The optimum temperature and pH for the hydrolysis of filefish muscle by papain, pepsin, $\alpha-chymotrypsin$ and protease were $50^{\circ}C,\;40^{\circ}C,\;55^{\circ}C\;and\;50^{\circ}C$; and 6, 2, 7 and 8, respectively. Those for incubation time and enzyme concentration were 4hr, $0.5\%$ for papain and protease, 24hrs $1.0\%$ for pepsin and $\alpha-chymotrypsin$. The pepsin was found to be more reasonable substrate for plastein synthesis from the economic point of view. The enzyme-induced plastein reaction could be optimized, namely, pH 4 for pepsin, pH 7 for $\alpha-chymotrypsin$, pH 6 for papain and protease: substrate concentration $40\%$ for pepsin, $\alpha-chymotrypsin$ and protease, $50\%$ for papain; the time of incubation, 24hr; enzyme/substrate ratio, 1 : 100(W/V) ; incubation temperature, $50^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.831-838
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• 1996

This study was undertaken in order to elucidate the effects of raw, roast and steamed buckwheat on fecal protein, Pancreas weight, the activities of $\alpha-amylase,$ chymotrypsin and lipase 91 the pancreas, and $\alpha-amylase,$ chymotrypsin and trypsin activities of the feces in streptozotocin-induced diabetic rats. Fecal proteins of raw, roast and steamed buckwheat diabetic groups were increased up to 99%, 91%, 103%, respectively compared to those of the diabetic control group. Feeding of buckwheat diet increased pancreas weight, especially raw buckwheat diabetic group(p<0.05). Pancreatic chymo-trypsin activity was decreased in buckwheat diabetic groups compared to diabetic control group, wheres any significant difference was observed in $\alpha-amylase$ and lipase activities. Fecal chymotrypsin activi-ty was significantly increased in all buckwheat diabetic groups. Fecal trypsin activity was increased in roast buckwheat diabetic groups compared to diabetic control group and fecal $\alpha-amylase$ activity in buckwheat diabetic group was not significantly different. These results suggest that feeding of buckwheat diet enhances the impaired exocrine pancreatic function of diabetic rat.

• KSBB Journal
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• v.9 no.3
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• pp.312-318
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• 1994

The esterification of Ac-Tyr-OH was carried out in one-phase system containing ethanol by ${\alpha}$-chymotrypsin. The results of the esterification reaction are as follows. Chitin-${\alpha}$-chymotrypsin complex was found to be an effective catalyst for the esterlfication of Ac-Tyr-OH in ethanol organic solvent. The optimal conditions for the esterification were chitn/${\alpha}$-chymotrypsin ratio, 20(w/w); reaction temp., $35^{\circ}C$; reaction pH, 8.0; reaction time, 24 hrs. Also, addition of chitin in water/water-miscible organic solvent was effective for the stability of the enzyme. The esterification yield, Km and Vmax under optimal conditions were 93%, 3.093mM and 1.088mM/mg/hr, respectively.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.676-681
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• 2001

This study was carried out to evaluate the quality characteristics of frozen soy yogurts prepared with different proteolytic enzymes and starter culture. The viable cell counts of lactic acid bacteria in frozen soy yogurts were measured $10^8$ CFU/g by the single culture method, while $10^9$ CFU/g by the mixed culture method except ${\alpha}-chymotrypsin$ treatment. The viable cell counts of lactic acid bacteria did not decrease after freezing for 30 min in ice cream maker. The lactic acid bacteria from the mixed culture showed better bile acid tolerance than those from the single culture. The lactic acid bacteria from the frozen soy yogurt prepared with ${\alpha}-chymotrypsin$ and mixed culture of Bifidobacterium bifidum and Lactobacillus bulgaricus showed better acid tolerance and bile acid tolerance. The highest(73.45%) overrun was observed in the frozen soy yogurt treated with ${\alpha}-chymotrypsin$ and mixed culture of B. bifidum and L. bulgaricus. The melt-down percent was higher in the single culture than the mixed culture. In sensory test, the frozen soy yogurt prepared with ${\alpha}-chymotrypsin$ and mixed culture of B. bifidum and L. bulgaricus was the most desirable, the highest scores in sourness, bitterness and mouthfeel.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.154-162
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• 2006

Cheese analogs using lipoxygenase-defected soymilk and ${\alpha}$-chymotrypsin modified soy protein isolate (SPI) were prepared. Color, textural properties, sensory attributes and melting spreadability of cheese analogs were evaluated and compared with mozzarella cheese, and relationships between textural properties, sensory attributes and melting spreadability of cheese analogs were analyzed. Off-flavors were not mostly discriminated. Cheese analogs containing 10% SPI untreated and containing 6% and 8% SPI treated by ${\alpha}$-chymotrypsin in ${\Delta}E$ value of color were the most similar to mozzarella cheese. Quality characteristics and melting spreadability of cheese analogs were highly affected and improved by ${\alpha}$-chymotrypsin modification. Sensory attributes and melting spreadability of cheese analogs containing 6% SPI treated by ${\alpha}$-chymotrypsin were the most similar to mozzarella cheese, while in textural properties, cheese analogs containing 10% SPI were the most similar with mozzarella cheese. Hardness in sensory attributes was highly positively correlated with hardness (r>0.65), adhesiveness (r>0.56), chewiness (r>0.77) and gumminess (r>0.76) in textural properties, while it was highly negatively correlated with melting spreadability (r>-0.68).

• Korean journal of food and cookery science
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• v.16 no.2
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• pp.151-159
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• 2000

The effects of bromelain and $\alpha$-chymotrypsin treatments on the functional properties(foaming capacity, foaming stability, emulsifying capacity, and emulsifying stability) of soy protein isolate(SPI) and the addition of various sweeteners(sucrose, sorbitol, xylitol) on the quality attributes(viscosity, overrun ratio, melt-down property, and sensory characteristic) of soy ice cream were studied. SPI was more effectively hydrolyzed with $\alpha$-chymotrypsin than bromelain, resulting in a better foaming and emulsifying capacity. Adding xylitol could significantly improve the viscosity, overrun and melt-down property of soy ice creams while the effect was the lowest in the sucrose addition. Bromelain treatment caused a lower apparent viscosity of SPI suspension compared with $\alpha$-chymotrypsin treatment and untreated. The overrun ratios of the soy ice cream prepared with bromelain and $\alpha$-chymotrypsin treated SPI were 18.9∼25.9% and 24.9∼40.3%, respectively as a result of freezing with agitation for 20 min in an ice cream maker. Comparatively, untreated SPI could bring only 15.8∼21.4% overrun ratios after operating for 15 min. The bromelain treatment caused high melt-down tendency of the product while soy ice cream with untreated SPI showed an opposite trend. In sensory characteristics, no significant differences in the strength of beany flavor were noted among the samples. Sweetness, bitter taste, icy feel, and mouthfeel of the product were greatly affected by the enzyme-treatment of SPI. Soy ice cream added with xylitol after $\alpha$-chymotrypsin treatment was the most acceptable among all samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.3
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• pp.233-241
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• 1988

In order to develop a new type of food source for the effective utilization of fish protein, plastein reaction was applied to improve the functional properties of sardine protein. Conditions necessary for optimal plastein productivity from sardine protein using pepsin, ${\alpha}-chymotrypsin$, protease(from Aspergillus saitoi) and papain were established. Sardine protein concentrate was hydrolyzed with pepsin yielding an approximate degree of hydrolysis of 78.4%. Enzyme induced plastein was optimized at : pH 4 for pepsin, pH 7 for ${\alpha}-chymotrypsin$, pH 5 for pretense and pH 6 for papain : Substrate concentrate 40% for pepsin and ${\alpha}-chymotrypsin$, 50% for pretense and papain : the time of incubation, 24hr : enzyme/substrate ratio, 1 : 100(w/v) incubation temperature, $50^{\circ}C$.