Marination of deep-water pink shrimp with rosemary extract and the determination of its shelf-life

The effect of the antioxidant activity of rosemary extract on marinated deep-water pink shrimp (Parapenaeus longirostris Lucas, 1846) stored at 1 °C was investigated. Chemical, physical, instrumental, microbiological and sensory analyses were performed to investigate the quality changes and to determine the shelf-life of marinated shrimps. Chemical composition of the shrimp was determined and no significant difference (P > 0.05) was found between the control group (without rosemary extract) and the experimental group (with rosemary extract). Both groups contained 2% citric acid. There was no significant difference (P > 0.05) between the sensory analysis of control and experimental groups on storage days 0, 15, 30, 45 and 60 while rancidity was noted by the panelists in the control group on day 75. The TBA value of the control group reached the consumption limit on day 75 but it was still ‘very good’ for the experimental group. Although the bacterial load of both groups were lower than the consumption limits on storage day 75, TBA value limited the shelf-life of the control group but the experimental group was still of good quality for consumption after 75 days.     

The use of a tea polyphenol dip to extend the shelf life of silver carp (Hypophthalmicthys molitrix) during storage in ice

The effects of a tea polyphenols (TP) dip treatment on quality changes of silver carp (Hypophthalmicthys molitrix) during iced storage were examined over a period of 35 days. TP (0.2%, w/v) solution was used for the dip treatment. The control and the treated fish samples were analysed periodically for microbiological (total viable count), chemical (pH, TVB-N, TBA, K-value), and sensory characteristics. The results indicated that the effect of the TP dip treatment on the fish samples was to enable the good quality characteristics to be retained for longer and to extend the shelf life during the iced storage.     

Effect of delayed icing on quality changes of iced rainbow trout (Onchorynchus mykiss)

The effect of delayed icing on quality deterioration of rainbow trout (Onchorynchus mykiss) iced 0, 4 and 8 h after catch was assessed by chemical, microbiological and sensory methods. Total volatile basic nitrogen (TVB-N), free fatty acids (FFA), peroxide value (PV) and thiobarbituric acid (TBA) values increased during the pre-icing duration. Delayed icing led to significant increased (p < 0.05) in total viable counts (TVC) throughout the period of storage. This study showed that sensory analysis of rainbow trout correlated well with microbiological analysis. Results of this study according microbiological and sensory data indicated that the shelf-life of rainbow trout stored in ice immediately after catch was approximately 9–11 days, while delay in icing for 4 and 8 h shortened the shelf-life was around 5–7 and 1–3 days, respectively.     

Effects of chitosan coating on quality and shelf life of silver carp during frozen storage

The effects of chitosan coating on quality and shelf life of silver carp during frozen storage were investigated. Fish samples were treated with aqueous solution of 2% chitosan, and then stored at −3 °C for 30 days. The control and the treated fish samples were analyzed periodically for microbiological (total viable count), chemical (pH, TBA, TVB-N, K-value), and sensory characteristics. The results indicated that the effect of chitosan coating on fish samples was to retain their good quality characteristics and extend the shelf life during frozen storage, which was supported by the results of microbiological, chemical, and sensory evaluation analyses.     

Chemical and microbiological quality of grass carp (Ctenopharyngodon idella) slaughtered by different methods

The effect of two slaughter methods (immersion in ice-water slurry and electrical stunning followed by ice slurry asphyxiation) on chemical and microbiological parameters of grass carp (Ctenopharyngodon idella) stored in ice for 20 days was evaluated. No differences in total volatile basic nitrogen (TVB-N), pH, carbohydrate or protein content of mucus were observed between the slaughter methods. Ice-slaughtered fish had lower bacteria counts at the beginning of storage, but higher counts than fish slaughtered by electricity at the end of storage (p < 0.05). However, no significant differences in the shelf life were observed between the slaughter methods evaluated (limit of acceptability – counts > 3 × 10⁶ CFU g⁻¹ – attained after 13–16 days). Results indicated that the chemical parameters evaluated have a limited applicability to assess the shelf life of grass carp stored in ice, since pH limit (6.8) was exceeded after 4 days, while TVB-N limit (30 mg%) was not attained after 20 days of storage.     

Postmortem changes in yellow grouper (Epinephelus awoara) fillets stored under vacuum packaging at 0 °C

The freshness of yellow grouper (Epinephelus awoara) stored under vacuum-packing at 0 °C was assessed by physicochemical, sensory and microbiological methods. No significant differences were found in pH and thiobarbituric acid (TBA) values during the storage, while TVB-N, TMA-N, HxR, Hx and K values increased significantly with time. The content of IMP was decreased significantly with the storage time. The texture profile, hardness and chewiness were significantly decreased with the time. L∗ values, the values of chroma and hue were all decreased. However, the increased b∗ values were observed. Furthermore, the significant variations and correlations of sensory attributes were shown with the storage time. A regression analysis for total viable counts yielded a shelf life of 26 days. This suggested that the TMA-N, IMP, HxR, Hx, K value, hardness, chewiness, colour, sensory attributes and microbiological counts may be considered suitable indicators for evaluating yellow grouper fillets spoilage during refrigerated storage.     

Sensory,physical, chemical and microbiological changes in aquacultured meagre (Argyrosomus regius) fillets during ice storage

Commercial-sized meagre fillets were stored on ice at 4 °C for 18 days, in order to evaluate the loss of quality and freshness that occurs over this period of time. Physicochemical (pH, thiobarbituric acid (TBA), total volatile basic nitrogen (TVBN), trimethylamine (TMA), water activity, water-holding capacity, colour, texture and fatty acid profile), sensory and microbiological analyses were carried out at 0, 4, 7, 11, 14 and 18 days of storage. As part of the sensory analysis, attributes associated with fillet appearance, odour and texture were examined. Variations in pH, TBA, TVBN and TMA were observed throughout the storage period, although only TBA displayed a significant correlation with time (r = 0.96). L^∗ and b^∗ values increased, and the chroma and hue values decreased, reflecting the colour changes experienced by the fillets over time. With regards to the texture profile, hardness was significantly correlated with time (−0.68). All the sensory analysis attributes exhibited significant variations and correlations close to 1.00 with storage time, which is a reflection of the fillets’ loss of freshness. The correlation coefficients between aerobic mesophilic and psychrophilic bacteria, enterobacteria and coliform counts on the one hand and storage time on the other were also very high (0.99–1.00). A regression analysis using the acceptability limit set by the ICMSF standard (1986) for total aerobic mesophilic counts (7 log cfu/g) yielded a shelf-life for meagre fillets of 9 days. The TBA, sensory and microbiological analyses displayed very strong correlations with storage time, and they may be considered suitable indicators for evaluating meagre fillet spoilage during refrigerated storage.     

竹叶抗氧化物结合壳聚糖对青鱼片贮藏品质的影响

为研究竹叶抗氧化物与壳聚糖复合保鲜剂对青鱼片的保鲜效果,将竹叶抗氧化物和壳聚糖配制成多组不同比例的复合保鲜剂,以挥发性盐基氮(total volatile basic nitrogen,TVB-N值)作为评价指标,筛选出抑制青鱼片中挥发性盐基氮生成最佳的复合保鲜剂组。将青鱼片经最佳复合保鲜剂组处理后,于4℃环境下贮藏,通过感官评价,硫代巴比妥酸(thiobarbituric acid,TBA值)、挥发性盐基氮(TVB-N值)、鲜度指标(K值)、菌落总数等主要指标的测定,研究青鱼片在冷藏期间的品质变化和货架期。结果表明:复合保鲜剂的最佳配比为3 g/L竹叶抗氧化物和15 g/L壳聚糖,青鱼经最佳复合保鲜剂处理后在4°C贮藏条件下菌落总数、TVB-N、TBA、K值均明显低于未经保鲜剂处理的对照组,而感官评分高于对照组,货架期可由6 d^8 d延长至12 d^14 d。     

天然复配保鲜剂及其与真空包装协同作用对预调理猪肉馅货架期的影响

目的:研究食品保鲜剂对预调理猪肉馅保鲜效果的影响,解决预调理猪肉馅易腐败变质且货架期极短的问题。方法:利用菌落总数或TBA值作为评价标准,测定经真空包装协同复配保鲜剂处理后的肉馅在贮藏期间理化指标及微生物指标的变化。结果:保鲜剂最优配比为0.049%乳酸链球菌素、0.207% D-异抗坏血酸钠、0.029%迷迭香提取物;真空包装协同复配保鲜剂处理能够有效延缓菌落总数、TBA值、TVB-N值、pH值的变化,且具有较好的感官评分,其货架期可达10 d。结论:真空包装协同复配保鲜剂处理预调理猪肉馅有较好的保鲜效果,能够有效延长其货架期。     

陇西腊肉复合保鲜剂配方优化

以陇西蕨麻猪肉为原料制备陇西腊肉,3℃条件下贮藏90d,以腊肉的感官评分、挥发性盐基氮含量和菌落总数为检测指标进行综合评价,通过单因素试验和响应面优化试验探究大蒜素、茶多酚、生姜提取物等天然保鲜剂对腊肉品质的影响.结果表明:单一保鲜剂的最适剂量为大蒜素质量浓度1.0g/100mL、茶多酚质量浓度3.0g/100mL、生...     

鲫鱼贮藏过程中微生物菌相PCR-DGGE分析及其防腐保鲜

采用聚合酶链式反应-变性梯度凝胶电泳(polymerase chain reaction-amplification and denaturing gradient gel electrophorsis,PCR-DGGE)技术,分析4℃冷藏条件下鲫鱼肌肉和鱼鳃的菌相组成及变化,并利用不同浓度(效价分别为67 608、32 359、2 239、1 820、1 157 IU/m L)抗菌脂肽溶液对鲫鱼进行浸泡处理,以未处理作为对照,分别测定其菌落总数、挥发性盐基氮(total volatile basic nitrogen,TVB-N)、p H值和硫代巴比妥酸(thiobarbituric acid,TBA)等指标,评价抗菌脂肽对鲫鱼冷藏保鲜效果。结果表明:鲫鱼贮藏过程中的微生物具有多样性,PCRDGGE技术确定气单胞菌属(Aeromonas sp.)、假单胞菌属(Pseudomonas sp.)、不动杆菌属(Acinetobacter sp.)和热杀索丝菌属(Brochothrix thermosphacta)为鲫鱼鱼肉的主要腐败菌群,荧光假单胞菌是鲫鱼贮藏过程中的优势腐败菌。而棉子糖乳球菌属(Lactococcus raffinolactis)、从毛单胞菌属(Comamonas sp.)和气单胞菌属(Aeromonas sp.)为鲫鱼鱼鳃的主要腐败菌群,表明鱼肉和鱼鳃在贮藏过程中,导致腐败的主要腐败菌群有一定差异性。同时,不同浓度的抗菌脂肽对鲫鱼均有明显的防腐保鲜作用,有效抑制了鲫鱼菌落总数、TVB-N值和TBA值的增加以及p H值的升高。其中,高浓度抗菌脂肽(效价为67 608 IU/m L)在4℃贮藏条件下使鲫鱼的货架期延长了6 d,说明抗菌脂肽对鲫鱼具有良好的保鲜作用,能明显延缓鲫鱼的腐败变质。     

Effect of thyme essential oil and packaging treatments on fresh Mediterranean swordfish fillets during storage at 4 °C

The present study evaluated the effect of thyme essential oil and packaging on fresh Mediterranean swordfish fillets during storage at 4 °C. Treatments in the present study included the following: air (A), modified atmosphere packaging (M), air with thyme oil (AT) and MAP with thyme oil (MT). Of the physicochemical parameters examined, TBA values for A and M swordfish samples were variable, indicative of no specific oxidative rancidity trend, whereas MT treatment inhibited lipid oxidation in swordfish samples during storage. On the basis of microbiological and sensory data, TMA-N and TVB-N limit values of acceptability for Mediterranean swordfish, of ca. 3.72 and 24.5 mg N/100 g, for the initiation of fresh Mediterranean swordfish spoilage, may be proposed. Of the treatments used in the present study, MT and M were the most effective for the inhibition of pseudomonads and H₂S-producing bacteria in swordfish. Lactic acid bacteria and Enterobacteriaceae (to a lesser extent) were also found to be part of the natural microbial flora of swordfish, irrespective of packaging treatment. Based primarily on sensory data, the shelf-lives of fresh refrigerated Mediterranean swordfish were 8 and 13 days under aerobic and MAP conditions, respectively. Addition of 0.1% thyme essential oil extended the product’s shelf-life under aerobic conditions by 5 days, whereas the combination of MAP and thyme oil resulted in a significant shelf-life extension of the swordfish fillets, i.e. by approximately 7½ days, according to sensory data, as compared to the control sample.     

A new technology for fish preservation by combined treatment with electrolyzed NaCl solutions and essential oil compounds

This study was undertaken to establish a new technology, using pre-treatment with electrolyzed NaCl solutions and essential oil compounds, to extend the shelf-life of carp fillets. Samples of skinless carp fillets were treated with 100-fold (by weight) of electrolyzed NaCl solutions [cathodic solution, EW(−) and/or anodic solution, EW(+)] and 1% oil (0.5% carvacrol + 0.5% thymol) [1%(C + T)]. Then chemical [pH, volatile basic nitrogen, peroxide value, and thiobarbituric acid], microbiological (total viable count) and sensory analyses were used to evaluate the preservative effect of this new technology during storage at 5 and 25 °C. Our results from the chemical assays indicated that EW(−), followed by EW(+) and subsequently 1%(C + T) [EW(−)/EW(+)/1%(C + T)], significantly suppressed the lipid oxidation compared with other treatments. Data from sensory evaluation and microbiological assay showed that treatment with EW(−)/EW(+)/1%(C + T) extended the shelf-life of carp fillets to 16 and 1.3 days compared with 4 and 0.3 days for the control samples during storage at 5 and 25 °C, respectively.     

竹醋液与茶多酚对牛肉的复合保鲜效果

考察了竹醋液与茶多酚对两种常见食源性致病菌大肠杆菌(革兰氏阴性菌)及金黄色葡萄球菌(革兰氏阳性菌)的最低抑菌浓度,进而将两者复配用于牛肉的保鲜。以储藏期间样品的pH值、挥发性盐基氮(TVB-N)值、菌落总数及硫代巴比妥酸(TBA)值为质量指标,研究竹醋液与茶多酚两者复配液对牛肉的保鲜效果。结果表明:竹醋液、茶多酚及二者复配液对牛肉有良好的保鲜效果,其中,复配液保鲜效果最佳,可将牛肉货架期由原来6~8 d延长到了12~14 d。     

Effects of sodium acetate dip treatment and vacuum-packaging on chemical,microbiological, textural and sensory changes of Pearlspot (Etroplus suratensis) during chill storage

The effects of sodium acetate dip treatment, followed by vacuum-packaging, on the shelf life of beheaded, scaled and gutted Pearlspot (Etroplus suratensis) during chill storage were examined. Sodium acetate (2%, w/v) solution was used for the dip treatment. Pouches (size: 15 × 22 cm) made of 12μ-polyester laminated with 300 gauge low-density polyethylene were used for packing fish. After packing, all the packs were iced with flake ice in the ratio (1:1) fish: ice in an insulated box and were kept in a cold room maintained at 0–2 °C. The control and the treated packs were analysed periodically for chemical (pH, TBA, TMA, TVB-N), microbiological (total viable count), textural and sensory characteristics. Changes in Staphylococcus aureus, Enterobacteriacea and Feacal streptococci were determined for fresh fish and for fish samples at the time of sensory rejection. Air packed samples were found to have a shelf life of about 8 days; vacuum-packed samples were found to be acceptable up to 10 days, whereas sodium acetate-treated vacuum packed samples were found to be acceptable up to 15 days. Thus, vacuum-packaging, in combination with sodium acetate, was found to delay the spoilage, thereby significantly extending the shelf life of Pearlspot at refrigeration temperatures.     

Chemical,microbiological and sensory changes of dried Acetes chinensis during accelerated storage

Chemical, microbiological and sensory changes of dried Acetes chinensis during 28 days of accelerated storage at 37 °C were studied. Eighty volatile components including alcohols, aldehydes, acids, ketones, esters, alkanes, nitrogen-containing components, aromatic components and terpenes were identified by headspace sampling and gas chromatography–mass spectrometry (GC–MS) method during storage. Among these volatile components, the relative content of trimethylamine was the highest during storage, which increased from 11.36 ± 1.02% at day 0 to 14.60 ± 0.58% at day 28. Values of total volatile base nitrogen (TVB-N), trimethylamine (TMA), thiobarturic acid reactive substances (TBARS), total viable mesophilic count (TVC) and sensory characteristics of colour and odour for dried A. chinensis changed significantly during storage. Volatile components, TVB-N, TMA, pH, TBARS, TVC, colour and odour characteristics at different storage time were statistically interpreted by principle component analysis (PCA) method in order to found the main indices for the freshness of dried A. chinensis. The results suggested that colour, TMA, TVB-N, TBARS, odour, TVC and some volatile components could reflect the quality changes perfectly.     

Effects of chilled storage on quality of vacuum packed meagre fillets

The aim of this study was to experimentally assess several quality indices of meagre Argyrosomus regius (Asso, 1801) fillets packed in air (AP) and vacuum (VP) stored chilled (+4 °C) for up to 13 days. Considering our experimental data on concentration of bacterial counts, shelf-life is estimated at ca. 6 days for AP fillets and an additional 3–5 days for VP meagre fillets. Total volatile basic nitrogen (TVB-N) and trimethylamine (TMA-N) did not reach the regulated limits (25–35 mg/100 g chilled fish). The models implemented in the software Seafood Spoilage and Safety Predictor predicted a relatively shorter shelf-life of 4.8–6.9 days for fish stored in air at +4 °C when compared to AP and VP fillets. Empirical data and the models implemented in the software were used to predict the shelf-life of fillets if packaged under different modified atmospheres (MAP). Chilled, MAP fillets are likely to have a longer shelf-life than AP or VP samples if equilibrium CO₂ concentration is substantially high.     

响应面法优化鲳鱼复合生物保鲜剂配方

为了保持鲳鱼块的食用品质,延长货架期,利用响应面Box-Behnken试验设计对茶多酚、溶菌酶和壳聚糖生物保鲜剂进行复配优化,建立以挥发性盐基氮（total volatile basis nitrogen,TVB-N）含量为响应值的二次多项式回归模型。并通过感官评定和菌落总数（aerobic plate count,APC）、TVB-N含量、硫代巴比妥酸（thiobarbituricacid,TBA）值、三甲胺（trimethylamine,TMA）含量、pH值和K值等指标测定对最优配比复合保鲜剂保鲜效果进行验证。结果表明：经方差分析和回归拟合,得到复合生物保鲜剂对鲳鱼块贮藏品质的最佳质量分数配比为：茶多酚1.35%、溶菌酶0.054%和壳聚糖1.38%,且溶菌酶与壳聚糖、茶多酚与壳聚糖对响应值存在显著的交互作用（P＜0.05）。该复合保鲜剂能够显著抑制微生物的生长（P＜0.05）,有效降低贮藏过程中TVB-N含量、TBA值、TMA含量,显著延缓鲳鱼块品质的变化,货架期较对照组（4 ℃冷藏）的5～6 d延长至12 d。     

壳聚糖和茶多酚对罗非鱼冷藏保鲜效果比较

本文以罗非鱼为原料,比较壳聚糖和茶多酚对罗非鱼冷藏保鲜的效果.以感官评分、细菌总数、pH值、挥发性盐基氮(TVB-N值)、硫代巴比妥酸(TBA值)、鲜度指标(K值)等作为质量指标,测定罗非鱼在4℃冷藏过程中品质变化.试验结果表明,经茶多酚和壳聚糖处理的罗非鱼再进行冷藏,罗非鱼的感官评分值下降缓慢,细菌总教、TVB-N值...     

Effect of gamma irradiation on microbial load and quality characteristics of minced camel meat

The effect of gamma irradiation on microbial load, chemical and sensory characteristics of camel meat has been evaluated. Camel meat was irradiated at doses of 0, 2, 4 and 6 kGy of gamma irradiation. Irradiated and non-irradiated meat was kept in a refrigerator (1–4 °C). General composition and sensory evaluation of camel meat was done two days after irradiation, whereas, microbiological and chemical analysis was done immediately after irradiation and throughout the storage periods. The results indicated that all doses of gamma irradiation reduced the total mesophilic aerobic plate counts (TPCs) and total coliforms of camel meat. Thus, the microbiological shelf-life of camel meat was significantly extended from less than 2 weeks (control) to more than 6 weeks (samples irradiated with 2, 4 or 6 kGy). No significant differences in moisture, protein, fat, thiobarbituric acid (TBA) values, total acidity and fatty acids of camel meat were observed due to irradiation. There were slight effects of gamma irradiation in both total volatile basic nitrogen (VBN) and lipid oxidation values in camel meat. Sensory evaluation showed no significant differences between irradiated and non-irradiated camel meats.