Use of chitosan to prolong mozzarella cheese shelf life

This study was undertaken to evaluate the feasibility of using chitosan, a natural antimicrobial substance, to improve the preservation of a very perishable cheese. The effectiveness of chitosan to inhibit the growth of spoilage microorganisms in Mozzarella cheese was studied during refrigerated storage. A lactic acid/chitosan solution was added directly to the starter used for Mozzarella cheese manufacturing. Mozzarella cheese samples were stored at 4°C for about 10 d and microbial populations as well as the pH were monitored. Results demonstrated that chitosan inhibited the growth of some spoilage microorganisms such as coliforms, whereas it did not influence the growth of other microorganisms, such as Micrococcaceae, and lightly stimulated lactic acid bacteria.     

焙烤食品货架期的影响因素和延长措施

介绍了影响焙烤食品货架期的因素,以及国内外对延长货架期采取的措施进行了综述.     

Effects of chitosan coating and storage position on quality and shelf life of eggs

Effects of chitosan coating and storage positions (small-end down, small-end up or horizontal) on internal quality and shelf life of eggs were evaluated during 5 weeks of storage at 25 °C. Compared with noncoated eggs, all chitosan-coated eggs, irrespective of storage positions, had significantly lesser weight loss, higher Haugh units and higher yolk index throughout the storage. Chitosan coating, irrespective of storage positions, extended the egg shelf life by at least 3 weeks at 25 °C compared with noncoated eggs. Noncoated and chitosan-coated eggs placed small-end down tentatively showed better quality than eggs placed small-end up after 3 and 4 weeks of storage. After 5 weeks of storage, storage positions did not significantly affect quality of noncoated and chitosan-coated eggs. There were no notable differences in total amino acid content of the albumen and fatty acid composition of the yolk between noncoated and chitosan-coated eggs after 5 weeks of storage.     

Development and evaluation of chitosan and its derivative for the shelf life extension of beef meat under refrigeration storage

The current study was aimed to study the shelf life of beef meat at refrigeration storage using novel chitosan derivative (Ch‐D). Chitosan was modified with antimicrobial monomethyl fumaric acid (MFA). The chemical structure of the resulting material was characterized by FT‐IR and HR‐XRD. The results confirmed the successful synthesis of conjugate sample. For the shelf life study, following lots were used: control (distilled water), chitosan 0.5%, Ch‐D 0.5%. The samples were kept at 4 °C for 16 days and analyzed at 4‐day intervals. Ch‐D treatment significantly reduced the total viable counts, enterobacteriaceae, lactic acid bacteria, psychrotrophic bacteria, and yeasts–moulds when compared with the chitosan and control during refrigeration storage. The peroxide value (PV) for Ch‐D was 0.19 ± 0.04 meq O₂ kg^?1 fat and chitosan was 0.21 ± 0.07 meq O₂ kg^?1 fat and showed no significant difference (P < 0.05) at the end of the storage. Thiobarbituric acid reactive substance (TBARs) value for Ch‐D was 0.48 ± 0.02 mg MDA kg^?1 and chitosan was 0.57 ± 0.09 mg MDA kg^?1, while the carbonyl contents for Ch‐D was 3.16 ± 0.23 nm  mg^?1 protein and chitosan was 3.11 ± 0.16 nm  mg^?1 protein at 16 days of storage. Values for Ch‐D and chitosan treatments were significantly lower (P < 0.05) for all the quality attributes as compared with the control throughout storage. At the end of storage, Ch‐D treatment showed a significant increase (P < 0.05) in lightness (L^* = 41.54 ± 0.09) and yellowness (b* = 2.23 ± 0.04). The redness for control was high (a* = 6.12 ± 0.09) as compared with the treated samples. Based primarily on microbial counts, Ch‐D treatment extended the shelf life of beef meat by about 8 days, maintaining acceptable quality attributes.     

Plasticizer types and coating methods affect quality and shelf life of eggs coated with chitosan

ABSTRACT:  Effects of different plasticizer types (glycerol, propylene glycol, and sorbitol) and coating methods (brushing, dipping, and spraying) on the internal quality and shelf life of chitosan-coated eggs were evaluated during 5 wk of storage at 25 °C. The Haugh unit and yolk index values suggested that chitosan coating, irrespective of the plasticizer types, extended the shelf life of eggs by almost 3 wk at 25 °C compared with noncoated eggs. After 5 wk of storage, plasticizer types did not significantly affect the quality (weight loss, Haugh unit, and yolk index) of chitosan-coated eggs. However, there was an observable trend indicating that use of sorbitol rather than propylene glycol and glycerol as a plasticizer was better in reducing weight loss (whole egg) of chitosan-coated eggs during a 5-wk storage. After a 5-wk storage, there were no significant differences in weight loss and weight of albumen and yolk among chitosan-coated eggs, regardless of the coating methods. However, both brushing and dipping methods yielded chitosan-coated eggs with better yolk (higher yolk index values) and albumen (lower pH) qualities than did the spraying method. During 3 to 5 wk of storage, the Haugh unit values of chitosan-coated eggs by the brushing method were higher than or comparable to those by dipping or spraying. Therefore, coating of eggs with chitosan using sorbitol as a plasticizer and by the brushing method may offer a protective barrier in preserving the internal quality and thus extending shelf life of eggs.     

Development of active chitosan films incorporating potassium sorbate or vanillin to extend the shelf life of butter cake

Active film from chitosan was developed by adding potassium sorbate or vanillin as antimicrobial agents. The addition of potassium sorbate in the film's formula resulted in less transparency, lower strength, water permeability, while increased flexibility and oxygen permeability. Addition of vanillin in film resulted in more yellow of film colour, lower film's strength and permeability. After that, all films were used to wrap around butter cake. The inhibitory effect of film against mould was studied using commercial stretch film as control. Mould was observed on cake wrapped by stretch film and chitosan film on day 4 and 7, respectively, while mould was not observed on cake wrapped by chitosan film containing potassium sorbate or vanillin during 8‐day storage which agreed with the amount of mould enumeration on PDA. The quality of cake during storage at room temperature was also studied. Cake wrapped with film containing vanillin became more yellow. The sensory of all cake treatments were acceptable.     

Application of nanoemulsion‐based approaches for improving the quality and safety of muscle foods: A comprehensive review

Recently, there has been growing interest in implementing innovative nanoscience‐based technologies to improve the health, safety, and quality of food products. A major thrust in this area has been to use nanoemulsions because they can easily be formulated with existing food ingredients and technologies. In particular, oil‐in‐water nanoemulsions, which consist of small oil droplets (<200 nm) dispersed in water, are being utilized as delivery systems for various hydrophobic substances in foods, including nutrients, nutraceuticals, antioxidants, antimicrobials, colors, and flavors. In this article, we focus on the application of nanoemulsion‐based delivery systems for improving the quality, safety, nutritional profile, and sensory attributes of muscle foods, such as meat and fish. The article also critically reviews the formulation and fabrication of food‐grade nanoemulsions, their potential benefits and limitations in muscle food systems.     

贮藏温度对鱿鱼品质变化的影响及其货架期分析

为探讨贮藏温度对鱿鱼品质变化及货架期的影响,研究了0、5、10、25℃贮藏条件下鱿鱼的色泽、pH、TVB-N、TMA、FA及TVC和感官分值的变化。结果表明,鱿鱼高品质期终点分别为357、180、118、19h,货架期终点分别为425、234、142、28h。贮藏过程中鱿鱼b*值、pH、TVB-N、TMA、TVC都有增加,FA随着贮藏时间呈先下降后上升的趋势。0、5、10、25℃贮藏的鱿鱼高品质期终点和货架期终点时的平均pH分别为（6.78±0.01）、（6.90±0.01）,TVB-N分别为（24.47±1.74）、（31.99±0.93）mg/100g,TMA分别为（6.71±0.90）、（10.23±0.30）mg/100g,FA分别为（1.65±0.94）、（4.22±0.34）mg/kg,TVC分别为（6.28±0.69）、（7.69±0.33）lgCFU/g。因此,贮藏温度越高,鱿鱼越容易腐败,货架期也越短,反之则对鱿鱼品质有利,可延长其货架期。      

壳聚糖溶液对豆腐保质期的影响

研究不同浓度壳聚糖溶液对豆腐保质期的影响。研究得出:壳聚糖添加量在1%时豆腐的感官评分较高,可在72 h内有效延缓pH降低,降低水分活度至0.78,可抑制大肠杆菌的增长,延长豆腐保质期3 d。     

电子鼻和电子舌在乳制品品质及货架期监控中的应用研究

基于仿生技术和传感器技术的电子鼻和电子舌技术的应用研究发展迅速。本文介绍了电子鼻和电子舌系统的构成和工作原理以及其在分析乳制品的风味、监控其储藏阶段的成熟或变质过程、控制原料乳的质量及掺假(杂)等方面的应用现状。      

Microgreen nutrition,food safety,and shelf life: A review

Microgreens have gained increasing popularity as food ingredients in recent years because of their high nutritional value and diverse sensorial characteristics. Microgreens are edible seedlings including vegetables and herbs, which have been used, primarily in the restaurant industry, to embellish cuisine since 1996. The rapidly growing microgreen industry faces many challenges. Microgreens share many characteristics with sprouts, and while they have not been associated with any foodborne illness outbreaks, they have recently been the subject of seven recalls. Thus, the potential to carry foodborne pathogens is there, and steps can and should be taken during production to reduce the likelihood of such incidents. One major limitation to the growth of the microgreen industry is the rapid quality deterioration that occurs soon after harvest, which keeps prices high and restricts commerce to local sales. Once harvested, microgreens easily dehydrate, wilt, decay and rapidly lose certain nutrients. Research has explored preharvest and postharvest interventions, such as calcium treatments, modified atmopsphere packaging, temperature control, and light, to maintain quality, augment nutritional value, and extend shelf life. However, more work is needed to optimize both production and storage conditions to improve the safety, quality, and shelf life of microgreens, thereby expanding potential markets.     

棕榈油品质对饼干保质期的影响

本文通过饼干的虐待储藏实验及风味品评实验，研究了棕榈油不同色泽及抗氧化剂TBHQ含量对饼干保质期的影响，并提出了饼干保质期达到12个月所要求的棕榈油质量指标。     

川味香肠货架期间理化品质变化规律研究

为了解川味香肠货架期中品质的变化以确保其安全性,本文选用产量较大的香肠为原料,测定了货架期中不同香肠水分含量、pH、蛋白质分解、脂肪氧化和亚硝酸盐含量以及微生物指标。结果表明:三种香肠pH和水分含量整体呈现下降趋势;挥发性盐基氮、AV、POV和TBA值均呈现上升趋势;亚硝酸盐随着水分含量的降低有所增加,但均未超标;散装晾挂产品的菌落总数呈现下降趋势,而真空包装产品略有升高,且在120~150d菌落总数增加明显;三种香肠的大肠菌群值均未超出国家标准,致病菌未检出。产品在货架期总体安全,真空包装较散装晾挂更能有效延长货架期,保证产品的理化品质。      

即食中华管鞭虾贮藏品质变化及其货架期研究

目的 探究贮藏期间,不同温度下(4、15、25和37℃)即食中华管鞭虾肌肉品质变化情况,并构建即食中华管鞭虾的货架期模型。方法 以即食中华管鞭虾为研究对象,测定不同温度下虾仁肌肉中挥发性盐基氮(total volatile basic nitrogen, TVB-N)含量、菌落总数、硫代巴比妥酸(thiobarbituric acid, TBA)值、色差、pH、持水力和感官评分变化,以虾仁肌肉TVB-N构建货架期模型。结果 随着贮藏时间的延长,不同温度下贮藏的即食中华管鞭虾肌肉TVB-N含量、菌落总数、TBA值和b*值均呈上升趋势;肌肉pH呈先下降后上升趋势;肌肉L*值和感官评分呈下降趋势,且贮藏温度越高,即食中华管鞭虾虾仁肌肉品质劣化越快。此外,受贮藏温度影响,4和15℃贮藏的虾仁肌肉持水力呈先上升后下降的趋势,而25和37℃贮藏虾仁肌肉持水力呈下降趋势。采用Pearson相关系数分析,确定了TVB-N含量和菌落总数为虾仁肌肉品质变化的关键性因子,其变化特征符合一级动力学模型。Arrhenius方程结果显示,虾仁TVB-N值的拟合精度更高,用TVB-N值建立货架期模型结果更为准确。通过模型验证发现,以虾仁肌肉TVB-N含量建立的货架期模型能够较为准确的预测其货架期。结论 贮藏温度升高会加速即食中华管鞭虾品质的劣化。4~37℃贮藏时,以虾仁肌肉TVB-N含量建立的货架期模型可较为准确地预测其货架期。     

Internal quality and shelf life of eggs coated with oils from different sources

Selected internal quality and shelf life of eggs coated with oils from differences sources (mineral oil, canola oil, corn oil, grape seed oil, olive oil, soybean oil, and sunflower oil) were evaluated during 5 wk of storage at 25 °C. As the storage time increased, weight loss increased whereas Haugh unit and yolk index values decreased. Throughout the 5 wk of storage, eggs coated with oils, regardless of oil sources, possessed better albumen and yolk quality than the control noncoated eggs. Oil coating minimized weight loss of eggs (<0.8%) compared with that (7.26%) of the noncoated eggs after 5 wk of storage at 25 °C. No significant differences in internal quality (weight loss, Haugh unit, yolk index, and albumen pH) were generally observed among oil-coated eggs during 5 wk of storage. Based on the Haugh unit, the grade of noncoated eggs changed from AA at 0 wk to A at 1 wk and to B after 3 wk whereas that of oil-coated eggs from AA at 0 wk to A at 4 wk and maintained A grade until 5 wk. This study demonstrated that oil coating, irrespective of oil sources, preserved the internal quality, minimized weight loss (<0.8%), and extended the shelf life of eggs by at least 3 wk longer than observed for the noncoated eggs at 25 °C storage. Soybean oil was a more practical option as a coating material for eggs due to its low cost. PRACTICAL APPLICATION: Eggs are highly perishable and susceptible to internal quality deterioration when stored above 7 °C. Refrigeration of eggs may be seldom practiced in some developing regions of the world. Therefore, an alternative method, that is inexpensive yet effective, to preserve the internal quality of eggs and to prevent microbial contamination is needed. Oil coating has been proven to preserve the internal quality, prolong shelf life, and minimize weight loss of eggs. This study demonstrated that, compared with other vegetable oils, soybean oil was a more practical option as a coating material for eggs during 5 wk of storage at 25 °C due to its low cost.     

低剂量辐照对鲜食核桃不同冷藏期后货架品质的影响

以\     

不同包装方式对蓝莓物流及货架期质构品质的影响

本实验选用6种不同包装方式对新鲜蓝莓进行物流模拟,物流时间分别为18、41和64h;利用质构仪质地多面分析方法（TPA）测定了物流结束时各包装中蓝莓的TPA参数,同时研究了物流后蓝莓货架期质构的变化规律。结果表明:在物流实验结束时,1号包装（预冷+自发气调保鲜袋（MAP）+蓄冷剂）中蓝莓的质构品质最好;在货架期内,蓝莓的硬度、内聚性、弹性、咀嚼性和回复性都随货架期时间的延长而下降,但1号包装（预冷+MAP+蓄冷剂）中蓝莓各项TPA参数均高于其它包装,表明1号包装中的蓝莓的品质最好。由此可确定1号包装为本实验中蓝莓物流的较好包装方式。      

H2O2喷雾处理对馒头品质及保质期的影响

采用H2O2喷雾处理的方法对馒头品质及保质期进行研究。结果表明:H2O2喷雾浓度和喷雾时间能明显影响其延长馒头保质期的效果。在H2O2喷雾浓度为20%、喷雾时间为5 s、静置时间为60 min时,馒头的保质时间从20 h延长至43 h,未检测出有残留的过氧化氢。     

Recent advances in extending the shelf life of fresh Agaricus mushrooms: a review

Postharvest browning of Agaricus mushrooms is a severe problem that reduces the shelf life of harvested mushrooms because of their continued respiration and biochemical activity. There are no simple answers and no single treatment is known to limit overall quality deterioration. However, there are several strategies that are being implemented in order to reduce the rate of respiration for mushrooms. Packaging technology is the common denominator that allows us to implement these strategies and thus is key to quality preservation. In this review, first, the major factors involved in postharvest quality deterioration are discussed and then technological advances/methods used to counteract these hurdles are presented. Copyright © 2010 Society of Chemical Industry     

泡菜货架期研究

研究了泡菜自然发酵的工艺及其货架期,结果表明,泡菜自然发酵的最佳条件为:6%的加盐量,发酵温度20℃,加入0.05?Cl2,发酵8~10 d。采用真空包装加冷藏后的泡菜保质期可达1年以上,加入0.05%的防腐剂可以延长保质期和改善产品质量。