Synergic Effects of Light Salting,Vacuum Packaging,and Onion Extract on the Quality Retention of Refrigerated Rainbow Trout (Oncorhynchus mykiss) Fillets

This experiment investigated the synergistic effects of vacuum packaging, light salting, and onion extract on the shelf life of rainbow trout (Oncorhynchus mykiss) fillets stored under refrigeration. The chemical, microbial, and organoleptic changes were monitored for up to 18 days in fillets. Total volatile basic nitrogen (TVB-N) and free fatty acid (FFA) values were evident in the order: control (without salting, vacuum packaging, and extract) > air packaged, salted (APS) > vacuum packaged, salted (VPS) > and vacuum packaged, salted, containing 2% and 4% (v/w) onion extract (2% and 4% VPSOE) throughout the storage period. Thiobarbituric acid values in APS groups were higher than control groups. Data from microbial assay showed that treatment with 2% and 4% VPSOE decreased total viable microbial count (TVC) compared with other treatments. APS, VPS, and VPSOE samples remained acceptable for up to 8, 12, and 15 days, respectively. The most suitable indices for determining shelf life of rainbow trout fillets are TVC.     

Preservation of Stuffed Mussels at 4°C in Modified Atmosphere Packaging

The stuffed mussel is a traditional, ready-to-eat food in Turkey which is produced by cooking rice and various spices filled inside the mussel. This article examines the effect on sensory, chemical, and microbiological parameters of stuffed mussels of two gas mixtures—MAP1 50% N₂/50% CO₂ and MAP2 100% CO₂—used as modified atmospheres for cold storage at +4°C. Air packaged samples were chosen as the control group. Based primarily on sensory characteristics, MAP1 gas mixture was the most effective for stuffed mussel. According to sensory results, it has been determined that the control samples kept until the 11th day, while the MAP1 and the MAP2 groups kept until the 13th day. Of the chemical indices determined, the TVB-N values of MAP1 and MAP2 remained lower than the proposed acceptability limits of 20 mg N/100 g, up to 13 days of storage. Microbiological analysis results did not find any differences between the groups. It was found that the shelf life of air and MAP1-MAP2 packaged samples were 7 and 11 days, respectively.     

Pasteurization Conditions and Evaluation of Quality Parameters of Frozen Packaged Crab Meat

ABSTRACT

Ovalipes trimaculatus is a crab recognized as a new resource with fishing value to obtain frozen products. Pasteurization conditions of meat crab at temperatures below 85ºC (60, 72, and 82ºC) were established to achieve better quality attributes in the frozen product. The lethality curves of Staphylococcus aureus and Listeria monocytogenes were measured, and the decimal reduction times (D) and Z values were determined. Heat transfer during the pasteurization process of pouches containing crab meat was simulated using a computational code in finite elements, and the mathematical model was experimentally validated. Thermal histories were coupled to the microbial lethality kinetics of the most heat resistant pathogen microorganism in order to establish pasteurization times necessary for the process system design. The predicted pasteurization conditions were microbiologically validated. The pouches were frozen under industrial conditions and stored at ?22ºC for 1 year. The influence of the type of packaging (vacuum and nonvacuum plastic pouches) on physicochemical and sensory quality parameters of frozen crab meat (color, exudate, lipid oxidation, water holding capacity, and overall acceptability) were analyzed observing better performance under vacuum conditions.     

Monitoring Quality of Packaged Pacific Ocean Perch (Sebastes alutus) in Storage

Pacific ocean perch stored under vacuum, 100% CO₂ or air at -3°C and 3°C was subjected to sensory, trimethylamine (TMA), color, microbial and volatile analyses. Unpleasant sensory attributes, TMA and microbial content were negatively correlated to overall quality, and Hunter 'L' value increased with storage time. Principal factor analysis of sensory data resulted in three factors that accounted for 71% of the variance, with factor 1 (53%) mainly related to poor quality attributes. Volatiles analyzed by the dynamic headspace technique included alkanes, alkenes, aldehydes, aromatics and alcohols. Canonical variate analysis on volatile compounds separated excellent and poor quality fish samples, while good and medium samples were grouped together.     

自然元素在农特产品包装设计中的生态呈现

用生态学和美学的观点论述了农特产品包装设计中的生态美,阐释了自然元素在农特产品包装设计中的审美呈现要素及其生态审美内涵,同时,也论述了农特产品包装设计必须具有的生态观及审美观。依据自然生态包装方式和理念,论述了自然生态元素在农特产品包装设计中的生态呈现形式和生态呈现理念。认为传统的包装工艺和理念应该与现代的生态理念相互融合,在改造利用自然的同时,也要顺应自然。在农特产品的包装设计中应该树立正确的包装生态观和审美观,提升对自然生态元素的利用水平,使农特产品包装得到更好的生态呈现。参16     

气调包装结合臭氧预处理保鲜鲟鱼片

本文研究了气调包装(MAP,50%CO2+10%O2+40%N2)结合臭氧处理用于鲟鱼片保鲜的效果。通过以未经过臭氧预处理的MAP做对照组,试验分别研究了臭氧预处理10min、20min和30min对鲟鱼片MAP保鲜期的影响。结果表明:臭氧预处理能有效减少鲟鱼片原始的带菌数,减缓贮藏期间细菌总数和TVB-N值的增加速度,以及减缓感官品质的下降。综合分析臭氧预处理时间对鲟鱼片贮藏期间感官品质、细菌总数、TVB-N值和肌肉持水力的影响,确定以臭氧预处理20min效果最好,与对照组比较,贮藏货架期延长3～5d。     

瑶山雪梨MAP常温保鲜效果研究

试验采用厚度0.03mmPE、0.03mmPVC和0.05mmPVC保鲜膜处理,以不扎口作对照,研究瑶山雪梨MAP常温保鲜效果。结果表明:20℃MAP贮藏35d,显著(P<0.05)抑制果实呼吸强度,降低果肉硬度、可溶性固形物和可滴定酸含量,减少果实失重率和腐烂率。其中,0.05mmPVC保鲜效果最好,稳定阶段袋内O23.5%～5.5%、CO26.0%～7.0%;贮藏35d,果肉硬度5.3kg·cm-2,可溶性固形物、可滴定酸、失重率和腐烂率分别为10.9%,0.076%,7.2%,30%。     

纳米抗菌包装对胚芽米储藏过程中陈化的抑制作用

【目的】胚芽米的营养价值相当丰富,具有广阔的市场前景,但其极易变质且不易储藏的现状是影响其推广的一大问题。探索胚芽米陈化过程中的成分变化及劣变情况,开发一种符合市场需求的、能够延缓胚芽米陈化的新型纳米抗菌包装材料。【方法】以五优稻4号胚芽米为试材,以普通聚乙烯包装材料为对照,分别制备两种不同的纳米抗菌包装材料,在常温环境下(25℃、65%湿度)储藏胚芽米28 d。每7 d取样一次,分别检测包装材料内部气体组成及胚芽米储存过程中菌落总数、脂肪酶活力、脂肪酸总量、淀粉糊化特性等指标;在初期和末期检测脂肪酸组成,胚芽米胚乳切面微观结构,以及纳米包装薄膜本身的抗菌性。比较抗菌性纳米包装材料对延缓胚芽米陈化的作用。【结果】包装袋内部气体组成检测数据表明,纳米包装材料改变了包装袋内部气体组成,降低了O2/CO2的比值,低氧环境也抑制了胚芽米的呼吸作用。抑菌性试验数据显示,两种纳米抗菌包装材料的抑菌性能较好,对大肠埃希氏菌与大米霉菌的抗菌率分别达99%与95%以上。普通包装下的胚芽米常温贮藏第28天菌落数即达41×10~4 cfu/g,而同期两种纳米包装下的胚芽米霉菌数仅分别为17×10~4 cfu/g与18×10~4 cfu/g(P0.05);抗菌包装中的胚芽米脂肪酶活性值较低,减少了游离脂肪酸的产生;胚芽米的脂肪酸组成适宜人体,较为合理,其初始不饱和比例为71.22%,贮藏28 d后普通包装下的胚芽米脂肪酸不饱和度为65.95%,而两种抗菌包装分别下降至69.10%与67.41%,变化幅度较小;抗菌包装中的胚芽米淀粉糊化特征值变化小,即口感劣变较慢;从胚乳切面微观结构上看,纳米抗菌包装材料在一定程度上具有延缓胚芽米陈化的作用,其内部淀粉质体裂解程度较低。【结论】常温环境下胚芽米陈化较快,霉菌繁殖、脂肪分解及结构等变化反应了胚芽米的陈化过程。纳米抗菌包装材料抑制了霉菌生长并能调节包装材料内部气体组成,达到降低胚芽米劣变速度与延缓陈化的作用。     

鸡蛋电子称量分级包装生产线自动控制系统设计与试验

鸡蛋质量分级是鸡蛋生产加工和销售前处理的重要工序之一,为了提高鸡蛋分级的生产效率和准确率,该文研究了一种用于鸡蛋电子称量、分级包装的同步跟踪自动控制系统,由称量部分、分级部分、装盘部分和自动送盘部分组成。利用一种32位嵌入式RISC处理器ARM同时采集多个通道传感器的鸡蛋质量信号并进行处理,将处理后的信息通过并行口送到可编程逻辑控制器PLC的寄存器,PLC对鸡蛋质量进行等级判断。利用限位开关脉冲作为数据传递的触发信号,然后利用编码器产生的高速脉冲实现对鸡蛋运动的位置精确定位,并控制相应的执行元件,配合机械装置的运动,解决了鸡蛋6排称量转单排线后的位置同步跟踪、对应电磁铁的准时动作和复位及分级之后鸡蛋自动装盘的难点,完成质量采集、分级卸料、装盘、送盘等动作,实现对不同质量等级范围鸡蛋的精确分级包装。试验结果表明,该控制系统测量误差在±1 g以内的鸡蛋占85.6%,分级准确率达到98%,生产效率为30 000枚/h,该研究结果有助于提高鸡蛋分级的生产效率,可为鸡蛋分级技术国产化提供参考。