平菇复合保鲜剂的筛选及保鲜效果

以平菇(Pleurotus ostyeatus)为实验材料,以贮藏期间的质量损失率、褐变度、呼吸强度以及感官指标(包括色泽、气味、腐烂程度、黏度等)为观测项目,采用单因素试验结合正交试验的方法研究不同质量浓度的保鲜剂柠檬酸、植酸、抗坏血酸、壳聚糖、食盐对平菇贮藏期间保鲜品质的影响。结果表明：保鲜剂质量浓度组合为柠檬酸10g/L、植酸1.5g/L、抗坏血酸1.3g/L。经此复合保鲜剂处理的平菇在(8 ± 1)℃可保存10d,其效果好于单一保鲜剂和蒸馏水对照。     

Industrial application of green chromatography - II. Separation and analysis of preservatives in skincare products using subcritical water chromatography

Several high-temperature liquid chromatography (HTLC) and subcritical water chromatography (SBWC) methods have been successfully developed in this study for separation and analysis of preservatives contained in Olay skincare creams. Efficient separation and quantitative analysis of preservatives have been achieved on four commercially available ZirChrom and Waters XBridge columns at temperatures ranging from 100 to 200°C. The quantification results obtained by both HTLC and SBWC methods developed for preservatives analysis are accurate and reproducible. A large number of replicate HTLC and SBWC runs also indicate no significant system building-up or interference for skincare cream analysis. Compared with traditional HPLC separation carried out at ambient temperature, the HTLC methods can save up to 90% methanol required in the HPLC mobile phase. However, the SBWC methods developed in this project completely eliminated the use of toxic organic solvents required in the HPLC mobile phase, thus saving a significant amount of money and making the environment greener. Although both homemade and commercial systems can accomplish SBWC separations, the SBWC methods using the commercial system for preservative analysis are recommended for industrial applications because they can be directly applied in industrial plant settings.     

不同防腐剂对油酥锅盔保质期的影响

对应用不同浓度纳他霉素（NT）、乳酸链球菌（Nisin）、双乙酸钠（SDA）和脱氢醋酸钠（DHA）处理的油酥锅盔的保质期效果进行了研究。结果表明,不同浓度的防腐剂可不同程度地抑制油酥锅盔表面的茵落生长。最优组合为NT：Nisin=8：2（0．24g/kg：O．04g／kg,保质期为33d）和NT：SDA=7：3（0．21g／kg：1．2g/kg,保质期为33d）,与对照组（保质期为20d）相比,大大延长了保质期。     

植物源天然防腐剂应用及抑菌机理研究现状

植物源天然防腐剂是一类从植物中提取出来的抑菌物质,天然绿色,是理想的抑菌防腐资源。我国食品行业正朝着营养健康的方向发展,消费者对食品安全的追求,都使得天然防腐剂的需求不断提升。该文综述了植物源天然防腐剂在动物性、水产、植物性和面制食品领域的应用现状及其抑菌机理,以期为植物源天然防腐剂在食品工业中的广泛应用提供思路。     

复合生物保鲜剂对金黄色葡萄球菌的抑菌作用研究

研究了壳聚糖、溶菌酶与茶多酚配制而成的复合保鲜剂对金黄色葡萄球菌的抑菌作用。采用琼脂平板打孔法确定复合保鲜剂对金黄色葡萄球菌的最小抑菌浓度(MIC)与最小杀菌浓度(MBC),结合抑菌率、抑菌活力、细菌生长曲线、膜完整性、AKP活性与细菌超微结构,综合评价复合保鲜剂对金黄色葡萄球菌的影响。结果得出,复合保鲜剂对金黄色葡萄球菌的MIC与MBC分别为0.8 mg/mL与1.6 mg/mL,随着作用时间的延长,复合保鲜剂对金黄色葡萄球菌的生长抑制明显,菌体的细胞壁与细胞膜完整性受到破坏,菌体细胞中的AKP量增多,影响菌体细胞的代谢循环,菌体内部的核酸与蛋白质外泄,抑制其正常生长。由细菌超微结构观察发现,菌体细胞经复合保鲜剂处理后,造成菌体扭曲变形,细胞壁破裂,细胞质外渗。表明复合保鲜剂可破坏菌体的细胞壁,影响胞膜稳定性与胞内环境,最终导致菌体死亡。     

Antimicrobial effectiveness of bioactive packaging materials from edible chitosan and casein polymers: assessment on carrot, cheese, and salami

Antimicrobial packaging is one of the most promising active packaging systems for controlling spoilage and pathogenic microorganisms. In this work, the intrinsic antimicrobial properties of chitosan (CH) were combined with the excellent thermoplastic and film-forming properties of sodium caseinate (SC) to prepare SC/CH film-forming solutions and films. The antimicrobial effectiveness of SC, CH, and SC/CH coatings on the native microfloras of cheese, salami, and carrots was evaluated. In vitro assays through the test tube assay indicated that the most significant antimicrobial effect was achieved by CH and SC/CH solutions on carrot and cheese native microfloras. SC film-forming solutions did not exert antimicrobial activity on any of the native microflora studied. SC, CH, and SC/CH films stored in controlled environments showed that the retention of the antimicrobial action was observed until 5-d storage, at 65% relative humidity in both temperatures (10 °C and 20 °C). In vivo assays were also performed with SC, CH, and SC/CH applied as coatings or wrappers on the 3 food substrates. CH and SC/CH applied at both immersion and wrapper exerted a significant bactericidal action on mesophilic, psychrotrophic, and yeasts and molds counts, showing the 3 microbial populations analyzed a significant reduction (2.0 to 4.5 log CFU/g). An improvement of the bactericidal properties of the CH/SC blend respect to those of the neat CH film is reported. The ionic interaction between both macromolecules enhances its antimicrobial properties. Practical Application: The continuous consumer interest in high quality and food safety, combined with environmental concerns has stimulated the development and study of biodegradable coatings that avoid the use of synthetic materials. Among them, edible coatings, obtained from generally recognized as safe (GRAS) materials, have the potential to reduce weight loss, respiration rate, and improve food appearance and integrity. They can be used in combination with other food preservation techniques in order to extend the effectiveness of the food preservation chain. Moreover, antimicrobial films and coatings have innovated the concept of active packaging and have been developed to reduce, inhibit, or delay the growth of microorganisms on the surface of food in contact with the package. The use of antimicrobials packaging films to control the growth of microorganisms in food can have a significant impact on shelf-life extension and food safety. In addition, antimicrobial films can be prepared by the combination of inherent antimicrobial materials (that is, CH), with good film-forming protein-based ones (that is, SC). Therefore, the objective of this work is to study the performance of 2 biodegradable and edible biopolymers and their combination as natural packages for selected food products.     

微生物源天然食品防腐剂的研究进展

天然食品防腐剂按其来源不同可分为植物源天然防腐剂、动物源天然防腐剂和微生物源天然防腐剂。微生物源天然食品防腐剂由于其本身的优越性,越来越受到人们的青睐。本文主要介绍了微生物来源的天然食品防腐剂乳酸链球菌素、ε-聚赖氨酸、曲酸、溶菌酶和甲烷氧化菌素的最新研究进展,阐述了它们的理化性质、抑菌机制和应用现状,同时简单介绍了纳他霉素、抗菌肽、罗伊氏菌素和嗜杀酵母等微生物源天然食品防腐剂的应用现状,旨在为高效、无毒、天然食品防腐剂的研究提供参考。天然食品防腐剂最有发展的可能是将几种来源不同的天然食品防腐剂复配,或者将一种天然防腐剂与其他化学防腐剂复配使用,不仅可以减少防腐剂在食品中的用量,同时还可以使食品的杀菌或抑菌条件更加温和化,对人们的饮食健康非常有利。     

生物防腐剂及其在食品中的应用

主要介绍了来源于植物、微生物及动物的天然生物防腐剂抗菌特性及其在食品加工中的应用。     

Nisin在酱油保鲜中的应用研究

通过对酿造酱油中G^ ,G^-菌组成情况的分析，研究了Nisin对酿造酱油中腐败细菌的抑制效力。对腐败细菌最适生长温度36℃下培养，当Nisin的含量达到100μg/ml时，营养肉汤（pH4.60)中腐败细菌的总数急剧减少，当Nisin的含量达到50－100μg/ml时，即能有效地抑杀酱油中的腐败细菌。这表明Nisin可替代化学防腐剂用于酱油的防腐保鲜，以减轻酱油的巴氏灭菌强度，保持酱油原有营养成分，风味，色泽，延长制品货架期。