• Asian-Australasian Journal of Animal Sciences
• /
• 제31권8호
• /
• pp.1291-1300
• /
• 2018

Objective: This experiment was conducted to investigate the effects of dietary crude protein (CP) level and exogenous protease supplementation on growth performance, serum metabolites, carcass traits, small intestinal morphology and endogenous protease activity in broiler chickens reared under a tropical climate. Methods: A total of 480 day-old male broiler chicks were randomly assigned to eight dietary treatments in a $4{\times}2$ factorial arrangement. The main effects were CP level (21.0%, 19.7%, 18.5%, or 17.2% from 1 to 21 days and 19.0%, 17.9%, 16.7%, or 15.6% from 22 to 35 days) and protease enzyme supplementation (0 ppm or 500 ppm). All experimental diets were fortified with synthetic feed-grade lysine, methionine, threonine and tryptophan to provide the minimum amino acid recommended levels for Cobb 500. Results: Reducing dietary CP linearly reduced (p<0.05) growth performance, serum albumin, total protein, and carcass traits and increased (p<0.05) serum triglycerides and abdominal fat. There was no consistent effect of reducing dietary CP on morphological parameters of the intestine and on the pancreatic and intestinal endogenous protease activity (p>0.05). Protease supplementation improved (p<0.05) feed conversion ratio, body weight gain, carcass yield and intestinal absorptive surface area. Conclusion: Protease supplementation, as measured by growth performance, intestinal morphology and carcass yield, may alleviate the detrimental effects of low protein diets in broiler chickens.

• 한국축산식품학회지
• /
• 제37권1호
• /
• pp.62-70
• /
• 2017

The aim of this study was identifying a suitable food grade enzymes to hydrolyze whey protein concentrates (WPCs), to give the highest bioactivity. WPCs from ultrafiltration retentate were adjusted to 35% protein (WPC-35) and hydrolyzed by enzymes, alcalase, ${\alpha}-chymotrypsin$, pepsin, protease M, protease S, and trypsin at different hydrolysis times (0, 0.5, 1, 2, 3, 4, and 5 h). These 36 types of hydrolysates were analyzed for their prominent peptides ${\beta}-lactoglobulin$ (${\beta}-Lg$) and ${\alpha}-lactalbumin$ (${\alpha}-La$), to identify the proteolytic activity of each enzyme. Protease S showed the highest proteolytic activity and angiotensin converting enzyme inhibitory activity of IC50, 0.099 mg/mL (91.55%) while trypsin showed the weakest effect. Antihypertensive and antioxidative peptides associated with ${\beta}-Lg$ hydrolysates were identified in WPC-35 hydrolysates (WPH-35) that hydrolyzed by the enzymes, trypsin and protease S. WPH-35 treated with protease S in 0.5 h, responded positively to usage as a bioactive component in different applications of pharmaceutical or related industries.

• 한국수산과학회지
• /
• 제48권2호
• /
• pp.178-186
• /
• 2015

Protease inhibitors (PI) of trypsin and papain as target proteases from the roe of bastard halibut Paralichthys olivaceus were fractionated out using ammonium sulfate precipitation (A), DEAE 650M anion exchange chromatography (D), and Sephacryl S-300 gel filtration (S). The recovery percentages of the fractions with the strongest inhibitory activity for each fractionation method were 13% for the A4 fraction, 21.2% for the D3 fraction, and 21.3% for the S2 fraction, with specific inhibitory activities of the fractions toward trypsin and casein of 168, 139, and 218 U/mg, respectively, while no inhibition of papain was observed. The $IC_{50}$ for the trypsin-specific substrate $N{\alpha}$-benzoyl-$\small{L}$-arginine-p-nitroanilide (BAPNA) was 0.65, 1.55, 2.26, and 2.85 mg/mL for the A4, S2, A3, and D3 fractions, respectively. These results suggest that chromatographic fractionation methods (D and S) based on the molecular mass and charge of the protein were more effective at fractionating PI than was ammonium sulfate precipitation based on protein solubility, and that the bastard halibut roe extract acts as a serine protease inhibitor. Therefore, the PI fraction from fish roe might be useful for inhibiting proteases in foodstuffs, and could constitute an alternative food-grade inhibitor for the surimi industry.

• 한국미생물·생명공학회지
• /
• 제34권2호
• /
• pp.115-120
• /
• 2006

천연 단백질인 실크를 가수분해하여, 건강기능성 식품 등에 다양하게 활용될 수 있는 가용성 실크 펩타이드를 생산하는 효소공학적 연구를 수행하였다. 효소는 Bacillus, Aspergillus, 파파야, 파인애플 등으로부터 유래하는 10종의 프로티아제를 사용하였으며,가수분해 효율을 높이기 위하여 생 실크를 $CaCl_2$- 에탄올 공용액에 녹인 가용화된 실크를 제조하였고, 이를 상온 중성의 조건에서 50시간 동안 투석하여 효소반응을 위한 기질로 사용하였다. 효소반응은 37, pH 7.0에서 수행하였으며, 파인애플 유래 프로티아제인 Bromelain과 Bacillus유래 효소인 Alcalase가 실크의 가수분해에 적합한 것으로 확인되었다. 특히 파인애플 유래의 Bromelain은 가수분해 도중 불용성 침전물의 형성으로 인한 생산 수율의 감소가 가장 적어 가용성 실크 펩타이드의 제조에 적합하였고, 분자량 분포에 있어서도 보다 다양한 것으로 확인되었다.

• 한국미생물·생명공학회지
• /
• 제29권1호
• /
• pp.1-11
• /
• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.

• Journal of Microbiology and Biotechnology
• /
• 제32권5호
• /
• pp.630-637
• /
• 2022

The objective of this study was to optimize industrial-grade media for improving the biomass production of Weissella cibaria JW15 (JW15) using a statistical approach. Eleven variables comprising three carbon sources (glucose, fructose, and sucrose), three nitrogen sources (protease peptone, yeast extract, and soy peptone), and five mineral sources (K₂HPO₄, potassium citrate, ⳑ-cysteine phosphate, MgSO₄, and MnSO₄) were screened by using the Plackett-Burman design. Consequently, glucose, sucrose, and soy peptone were used as significant variables in response surface methodology (RSM). The composition of the optimal medium (OM) was 22.35 g/l glucose, 15.57 g/l sucrose, and 10.05 g/l soy peptone, 2.0 g/l K₂HPO₄, 5.0 g/l sodium acetate, 0.1 g/l MgSO₄·7H₂O, 0.05 g/l MnSO₄·H₂O, and 1.0 g/l Tween 80. The OM significantly improved the biomass production of JW15 over an established commercial medium (MRS). After fermenting OM, the dry cell weight of JW15 was 4.89 g/l, which was comparable to the predicted value (4.77 g/l), and 1.67 times higher than that of the MRS medium (3.02 g/l). Correspondingly, JW15 showed a rapid and increased production of lactic and acetic acid in the OM. To perform a scale-up validation, batch fermentation was executed in a 5-l bioreactor at 37℃ with or without a pH control at 6.0 ± 0.1. The biomass production of JW15 significantly improved (1.98 times higher) under the pH control, and the cost of OM was reduced by two-thirds compared to that in the MRS medium. In conclusion, OM may be utilized for mass producing JW15 for industrial use.

• Journal of Animal Science and Technology
• /
• 제45권2호
• /
• pp.309-318
• /
• 2003

본 연구는 저급한우갈비의 이용을 용이하게 하기 위해 건 양념에 키위, 배 등의 식물성 천연연화제를 첨가하여 저급양념한우갈비의 연도 개선 효과를 알아보고, 품질개선제를 첨가하여 품질개선 효과를 알아보고자 실시되었다.K0.1(키위분말 0.1%), K0.3(키위분말 0.3%), K0.5(키위분말 0.5%)를 첨가한 양념갈비의 MFI value는 각각 341.43$\pm$2.98, 368.31$\pm$10.95, 405.10 $\pm$5.82로 첨가량이 증가할수록 MFI value가 증가하였으며(P<0.001), P0.5(배분말 0.5%), P1.0(배분말 1.0%), P3.0(배분말 3.0%)를 첨가한 양념갈비에서도 첨가량이 증가할수록 MFI value가 증가하였다. 하지만, 배분말의 경우 갈비중량당 3.0% 정도 첨가시 확실한 연육효과가 기대되며, 배분말이 3.0%를 초과할시 더 큰 연육효과는 기대되지만, 갈비표면적보다 배분말의 부피가 역전되어 실효성이 없을 것으로 판단된다. 품질개선제로 CS(Polymix-CS)를 첨가한 경우 0.3% 수준 이상 첨가시 연육효과가 있었고, CS0.3과 CS0.5 처리구에서는 비슷한 MFI value를 나타내었다. 보수력(WHC)을 알아본 실험에서는 키위분말, 배분말 모두 첨가량이 증가할수록 보수력이 저하되었는데(P<0.001), 이러한 현상은 키위의 actinidin의 활성과, 배의 protease 성분으로 기인된 것으로 사료된다. 반면, 품질개선제를 첨가한 CS0.1, CS0.3, CS0.5 처리구에서는 첨가량이 증가할수록 보수력이 증가하였다. Drip loss의 경우는 보수력과 마찬가지로 키위분말과 배분말은 첨가량이 증가할수록 drip loss도 증가하였고, 반대로 품질개선제는 첨가량이 증가할수록 drip loss가 감소하는 경향을 보였다. Meat color는 양념과 혼합처리시 L*-value의 측정결과는 배분말 처리구에서 control과 유사한 값을 보였고, a*-value는 키위분말 0.1${\sim}$0.3%, 배분말 0.5${\sim}$1.0%, CS 0.3${\sim}$0.5 수준의 첨가시 control 보다 향상된 값을 보였다. 하지만, 양념갈비의 육색은 양념중 약 70%를 차지하는 설탕과 마늘 등으로 인한 심한 변색으로 첨가제의 첨가로 인한 육색의 안정 및 향상은 힘들 것으로 보인다. 관능검사의 경우 양념과 혼합처리시 Juiciness (P<0.01), Tenderness(P<0.001), Acceptability (P< 0.001) 항목에서 K0.3과 CS0.5 처리구가 전체적으로 높은 관능 수치를 나타내었으며, 배분말 중에서는 P3.0 처리구가 가장 높은 Accept- ability를 나타내었다. 또한 기타 항목에서는 갈비양념 성분으로 인해 유의차가 없었던 것으로 생각되며, 전체적으로 Acceptability는 Tender- ness, Juiciness와 밀접한 관계가 있음이 확인되었다. 본 실험에서 천연연화제로 사용한 키위분말과 배분말은 모두 식육연육효과를 가지고 있는 것으로 확인되었으며, 혼합인산염을 통한 품질개선효과도 확인하였다. 특히 키위는 적은 양으로도 연육효과가 있어, 앞으로 저급한우갈비에 효과적인 사용이 기대된다.