• 한국수산과학회지
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• 제54권5호
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• pp.724-732
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• 2021

This study used response surface methodology to investigate the optimal conditions to reduce the bitterness of alcalase-treated anchovy hydrolysate (AAH) by the aminopeptidase active fraction (AAF) derived from the common squid Todarodes pacificus hepatopancreas. The central composite design selected AAF/AAH ratio (X₁, %) and hydrolysis time (X₂, h) as independent variables, and the degree of hydrolysis (Y₁) and bitterness (Y₂) as dependent variables. The uncoded values of the multiple response optimization for independent variables were 3.4% for the AAF/AAH ratio and 9.2 h for the hydrolysis time. The predicted values of the yield and bitterness score of alcalase-AAF continuously treated anchovy hydrolysate (AAAH) under the optimized conditions were 68.9% and 4.6 points, respectively. Their measured values of 69.5% for yield and 4.6±0.5 points for bitterness were similar to the predicted values. The food components of AAAH were 91.4% (moisture), 7.5% (protein), 0.1% (lipid) and 0.6% (ash). The findings indicate the potential value for use as an anchovy seasoning base. The results also confirm that the bitterness of AAH was remarkably improved by AAF and implicates AAF derived from squid hepatopancreas as a good enzyme to catalyze reduced bitterness.

• 한국수산과학회지
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• 제53권1호
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• pp.112-122
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• 2020

This study investigated some enzymatic properties and bitterness improvement of an aminopeptidase retentate fraction (ARF) from common squid Todarodes pacificus hepatopancreas extract (HPE), obtained by ultrafiltration with a 10 kDa molecular weight cut off membrane. Endoprotease and aminopeptidase (AP) activity, and the purity of the ARF (>10 kDa) increased by 6.69-18.11 U/mg and 1.5-2.6 fold, respectively, compared to HPE (2.63-9.37 U/mg). The AP activity toward LeuPNA was stable at 20-55℃ and pH 5-9, but decreased slightly with increasing concentration of NaCl in the reaction mixture. The ARF was the most active MetPNA and preferentially hydrolyzed Glu, Leu and AlaPNA. The bitterness tryptic casein hydrolysates (BTCHs) were treated with ARF, and the bitterness of ARF-BTCHs significantly decreased with increasing amounts of released amino acids Ala, Val, Met, Ile and Leu, which show strong correlations with bitterness. Therefore, the ARF of T. pacificus HPE obtained by ultrafiltration may have a considerable potential for application in protein hydrolysis and appears to be ideally suited to the purpose of lowing bitterness in protein hydrolysates.

• 한국식품과학회지
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• 제46권6호
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• pp.716-722
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• 2014

국내산 살 오징어 간췌장 조효소를 추출한 다음, 단백질 성질에 기초한 분획방법(용해도, 전기적 성질 및 분자량크기)으로 분획한 endoprotease 및 aminopeptidase 활성 획분들에 대한 분해 활성 비교한 다음, 이들 획분의 반응시간에 따른 쓴맛 casein 가수분해물의 쓴맛 개선 효과를 효소활성, 관능검사 및 HPLC 크로마토그램을 통하여 살펴보았다. 분획방법별 각 획분의 쓴맛 평가에 의한 쓴맛 개선 효과는 겔 여과법에 의하여 분획된 획분(GF-I, 30-50 kDa)이 가장 효과적이었다. GF-I 획분을 2% Gly-phe에 준하는 쓴맛 casein 가수분해물에 대하여 1/500의 비율로 첨가한 다음, 16시간 이상 반응시킨 가수분해물은 HPLC 크로마토그램 상에서 친수성이 강한 피크면적(피크 1, 2 및 4)은 증가한 반면, 소수성이 상대적으로 강한 피크면적(피크 3, 5 및 6)가 감소하였으며, 쓴맛 평가 결과에서도 쓴맛 개선 효과가 뚜렷하였다. 앞으로의 연구에서는 오징어 간췌장 유래 aminopeptidase의 효율적인 산업적 이용을 위한 단백질 분자량 크기에 따른 연속분획 공정을 통한 대량회수 방법 및 쓴맛 개선 가수분해물로부터 유리된 아미노산분석, 효소안정성, 기질특이성 등에 대하여 진행하고자 한다.

• 한국수산과학회지
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• 제54권6호
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• pp.849-860
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• 2021

This study investigated the preparation of seasoned anchovy sauce (SAS) and its functional characteristics by using aminopeptidase active fractions (AAFs) derived from squid Todarodes pacificus hepatopancreas as a bitter taste improver. As the base of the SAS, a hydrolysate (AAAH) prepared by continuously treating raw anchovies with Alcalase-AAF was used. The high-performance liquid chromatography profile of the AAAH suggested that the action of AAFs decreased the hydrophobicity of the N-terminal peptide related to bitterness in the protein hydrolysates. SAS was prepared by blending with the AAAH and other ingredients. The crude protein (2.5%), carbohydrates (18.4%), amino acid-nitrogen (1,325.1 mg/100 mL), and total free and released amino acids (FRAAs, 700.2 mg/100 mL) of SAS were higher than those of commercial anchovy sauce (CAS). Sensory evaluation revealed that SAS was superior to CAS in flavor, color, and taste. The main FRAAs of SAS were glycine (16.8%), alanine (13.2%), glutamic acid (7.8%), and leucine (7.3%). The amino acids that had a major influence on the taste according to the SAS taste values were glutamic acid, aspartic acid, alanine, and histidine. The angiotensin-converting enzyme inhibitory (2.21 mg/mL) and antioxidant activities (3.58 mg/mL) of SAS were superior to those of CAS.

• 한국수산과학회지
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• 제47권2호
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• pp.135-143
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• 2014

Exopeptidase active fractions from the hepatopancreas of the Argentina shortfin squid Illex argentinus, were obtained with acetone (AC 30-40%), ammonium sulfate (AS 60-70% saturation), anion exchange chromatography (AE-II, 0.2 M NaCl) and gel filtration chromatography (GF-I, 30-50 kDa) fractionation methods. A bitter peptide solution that has a bitterness equivalent to that of 2% glycylphenylalanine and prepared by tryptic hydrolysis of milk casein, was treated with the exopeptidase active fractions. The GF-I fraction was the best based on aminopeptidase activity (35.3 U/mg), percentage of recovery (30.7%) and a sensory evaluation (1.7). The amount of released amino acids increased as incubation time increased, and the bitterness of the enzyme reaction mixtures decreased. Incubation with the GF-I fraction for 24 h resulted in the hydrolysis of several peptides as revealed by the reverse-phase high performance liguid chromatography profile, with three peaks (3, 5 and 6) decreasing in area (%) and three peaks (1, 2 and 4) increasing in area (%). Therefore, the GF-I fraction appeared to be ideally suited to reduce bitterness in protein hydrolysates by catalyzing the hydrolysis of bitter peptides.