Antioxidant and anti‐acetylcholinesterase activities of anchovy (Coilia mystus) protein hydrolysates and their memory‐improving effects on scopolamine‐induced amnesia mice

Anchovy protein hydrolysates (APHs) were prepared through hydrolysis for 2, 4 or 8 h (APH‐2, APH‐4 and APH‐8, respectively). The chemical analyses, in vitro assessments [antioxidant activity and acetylcholinesterase (AchE) inhibitory activity] and in vivo mice tests were evaluated. Results revealed that APH‐8 exhibited the strongest reducing power and AchE inhibitory capacity (IC₅₀ = 159.76 ± 0.03 mg mL^?1), which may be due to its specific amino acid composition and newly formed peptides. In addition, AchE inhibitory kinetics of amino acids suggested that lysine was featured of both competitive and noncompetitive inhibitors. Furthermore, the results of in vivo study showed that all APHs exhibited memory‐improving action on scopolamine‐induced amnesia mice especially, APH‐8, indicating that anchovy protein is a potential source for health‐promoting peptides.     

N-nitrosamine reduction in salted and fermented anchovy sauce by ionizing irradiation

Salted and fermented anchovy sauce spiked with or without N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) was irradiated at 0, 5, 10, 15 and 20 kGy. NDMA and NPYR reduction by irradiation was not observed in non-spiked samples at 0 week, while a significant reduction was observed after 4 weeks of storage at 15 °C (P<0.05). In N-nitrosamine spiked samples, a positive effect of irradiation on NDMA and NPYR reduction was observed. NDMA and NPYR levels were decreased by irradiation at 5 kGy or above after storage. Therefore, gamma irradiation has a possibility to reduce N-nitrosamines in salted and fermented anchovy sauce.     

Evaluation of Histamine and Other Biogenic Amines and Bacterial Isolation in Canned Anchovies Recalled by the USFDA

ABSTRACT: Histamine and other biogenic amines were evaluated in canned anchovies recalled by the U.S. Food and Drug Administration. In addition, bacteria were isolated from the products and identified to species. The recalled products were divided into 2 groups of high and low histamine, depending on the histamine contents as determined by the AOAC method. The high histamine group had the histamine contents >200 ppm, and 24 of the 30 cans analyzed belonged to this group. The most prevalent biogenic amine in this group was histamine followed by cadaverine. On the other hand, the low histamine group of 6 cans contained approximately 50 ppm histamine. The most prevalent biogenic amine found in this group of samples was cadaverine at levels >200 ppm. Other biogenic amines, such as putrescine, serotonin, and spermidine, were also detected in all the products, although at varied levels. Aerobic and anaerobic bacterial counts, if present in all of the recalled products, were below the detection limit of 10² colony-forming units (CFU)/g. Bacteria were recovered only after enrichment of the test samples. They were mostly halophilic bacteria. Bacillus spp. were most frequently identified, followed by Staphylococcus spp. However, these isolates produced negligible amounts of histamine in culture broth, indicating that they are not the contributors to histamine accumulation in the canned anchovies.     

Influence of Raw Fish Quality on Some Physicochemical and Microbial Characteristics as Related to Ripening of Salted Anchovies (Engraulis encrasicholus L)

Influence of raw fish quality on the sensorial, physicochemical, and microbiological characteristics as related to ripening of salted anchovies has been studied. Raw fish remained iced for 4 d and samples were periodically taken for processing following traditional methods on d 0 (Extra: high quality fish), 2 (A: medium quality fish) and 4 (B: inedible as human food). The enzymatic activity is not suppressed when the ripening period is completed and alkaline proteinase activity dominates. No statistical differences were observed in the sensory assessment and in the majority of physicochemical and microbiological data obtained during the ripening process. However, differences are observed when raw material is of grade C (low quality fish), especially in the proteinase activity at pH 9.     

Survey of the histamine content in fish samples randomly selected from the Greek retail market

The histamine content of fish sold in the Greek retail market was surveyed and the performance of high-performance liquid chromatography (HPLC) and enzyme-linked immunoabsorbant assay (ELISA) methods for the determination of histamine were compared. A total of 125 samples of fresh and canned tuna, fresh and canned sardines, deep frozen swordfish, smoked and deep frozen mackerel, anchovies, salted and smoked herring were analysed by HPLC (55 samples), ELISA (106 samples) and both methods (36 samples). Histamine levels as determined by HPLC, ranged from 2.7 mg kg^?1 to 220 mg kg^?1. The highest histamine concentrations obtained by HPLC were found in herring and anchovy samples. Eight out of the 55 samples (14.5%) analysed by HPLC, exceeded the US Food and Drug Administration (USFDA) limit (50 mg kg^?1), while 16 out of the 106 samples (15%) analysed by ELISA exceeded the limit. The results show that for histamine concentrations below 50 mg kg^?1, there is good agreement between the ELISA and HPLC but above 50 mg kg^?1 big differences were found.     

黄鲫胃蛋白酶酶解液体外抗氧化、抑菌作用研究

采用胃蛋白酶水解黄鲫,测定酶解液的蛋白提取率、可溶性肽含量、水解度及氨基酸组成,并对酶解液体外抗氧化和抑菌作用进行研究。结果表明：黄鲫胃蛋白酶酶解液的蛋白提取率、可溶性肽提取率、水解度分别为 (110.28 ± 4.81)%、(81.78 ± 0.04)% 和 (18.12 ± 0.39)%,黄鲫胃蛋白酶酶解液的人体必需氨基酸相对含量可达37.91%。黄鲫胃蛋白酶酶解液具有很强的抗氧化能力,清除羟自由基和DPPH 自由基的ED50 分别为4.55μg/mL 和4.46μg/mL,还原力随着黄鲫胃蛋白酶酶解液质量浓度的增加而增大,在3.4 μg/mL 和13.6μg/mL 低、中质量浓度时螯合金属离子能力与EDTA 接近。体外抑菌实验显示：黄鲫胃蛋白酶酶解液具有广谱抑菌性,对大肠杆菌的抑菌效力分别与 13.21～15.44mcg/mL 的氨苄青霉素和 325.00～340.00U/mL 的硫酸链霉素相当 (P ＞ 0.05)。     

基于HS-SPME-GC-MS分析风味鱼仔加工过程中风味物质的变化

本文研究了卤料包循环熬制对熟制小鱼干风味的影响。采用电子舌研究经第一锅卤水卤制的成品风味小鱼干A和第五锅卤水卤制的成品风味小鱼干B的风味差异。通过电子鼻和顶空固相微萃取-气质联用（Headspace solid-phase microextraction-mass spectrometry coupled with gas chromatography-mass spectrometry,HS-SPME-GC-MS）对A、B样品中的挥发性化合物进行分析。结果表明：电子舌中,经第五锅卤水油炸卤制后的风味小鱼干B在鲜味、苦味和咸味更强。从电子鼻结果来看,A、B样品的差异主要体现在W2W（有机硫类）、W1S（甲烷短链烷烃类气体）和W1W（硫化物）传感器上,前两者在小鱼干B中有所减少,而W1W（硫化物）则有所增加。通过GC-MS从两种产品中共检测出62种挥发性物质：A样品中检测出了45种物质,B样品中检测出了54种物质。共同检测到的物质有36种,其中相对含量较高的主体风味物质包括芳樟醇、茴香烯、乙酸芳樟酯和4-烯丙基苯甲醚等在风味小鱼干B中含量更高。综上,卤水的循环熬制有利于促进小鱼干中有益挥发性风味物质的生成以及香辛料中风味物质的融出。这可为后续风味熟制小鱼干的技术优化提供理论支持。     

Thermostable Proteinase in Salted Anchovy Muscle

Salted anchovy fillets produced in Japan were severely degraded above 35°C and were solubilized completely in a few hours at 55°C. In contrast, raw anchovy fillets were not solubilized, but the solubility of fillets gradually increased during the salting process. In contrast, salted and raw anchovy fillets from southern Europe were relatively stable. Proteolytic activity that digested myosin heavy chain in vitro was found in muscle extracts from both types of salted fillets. Enzymes with activity were high-temperature-active serine proteinases with substrate specificities similar to trypsin. Optimal pH was 7.4 (Japan) and >8.5 (Europe). Neither enzyme showed collagen-degrading activity.