糖渍大蒜酸败的原因浅析

为了防止糖渍大蒜发生酸败变质,分析了糖渍大蒜产生酸败的原因,提出了预防糖渍大蒜酸败变质的措施,并对酸败的糖渍大蒜进行除去无食用价值的部分,再进行二次加工处理,同时加强检验。     

Rancidity in hazelnuts due to volatile aliphatic aldehydes

Hazelnut kernels became rancid on storage under ambient conditions in the presence of air. The kernels have a high oil content. The oil contains approximately 75 g per 100 g oleic acid (18:1) and 9 g per 100 g linoleic acid (18:2). Rancidity was detected organoleptically, by gas chromatography/mass spectrometry of the volatile off-flavour compounds and by reduction in both the total fatty acid content (g per 100 g oil) and the iodine value (g per 100 g oil). There was an accumulation of volatile alkanals, 2-alkenals and alkanoic acids on storage of the kernels at ambient temperature in the presence of oxygen. Hexanal (derived from oxidation of linoleic acid) and octanal (derived from oxidation of oleic acid) increased over tenfold on storage, whilst there was concomitant decrease in fatty acid content (83 g per 100 g oil) and iodine value (79) during the same period. It is suggested that analysis of volatile aldehydes such as hexanal and octanal could be used to assess rancidity in foods or oils rather than relatively nonspecific tests such as iodine or peroxide value. There was no evidence in this work that the rancidity was due to microbial spoilage.     

核桃仁氧化酸败及其延缓措施研究进展

核桃是世界四大干果之一,果仁营养丰富,经济价值颇高。但由于核桃仁脂肪含量高,贮藏中易出现脂肪氧化酸败现象。对核桃仁氧化酸败的机理及影响酸败的温度、相对湿度、氧气、光照、含水量等因素进行探讨。同时,综述延缓核桃仁氧化酸败的相应措施,以期为核桃仁的大规模贮藏提供理论参考。     

The effect of salt concentration on rancidity in Gaziantep cheese

Gaziantep cheese is a non‐fermented and enzyme clotted type cheese. The changes in oxidative and hydrolytic rancidity in the cheese were analysed during its storage. Storage conditions were selected as 4, 10 and 20°C and 90, 170, 200 and 230 g kg⁻¹ salt solutions by considering the traditional storage conditions. Oxidative rancidity increased with increasing temperature and NaCl concentration in the brine. Hydrolytic rancidity increased with increasing temperature and decreasing salt content of the cheese. The extent of oxidative rancidity was found to be higher than hydrolytic rancidity. The results of this study showed that the storage temperature should not be higher than 10°C and brine concentration must be higher than 90 g kg⁻¹ and lower than 230 g kg⁻¹ to minimize lipid oxidation. Gaziantep cheese was organoleptically examined after 2 months of storage at 20°C and in 90, 170 and 230 g kg⁻¹ salt solutions, and it was found that even at a peroxide value around 1 meq kg⁻¹, acceptable levels of changes in flavour were observed. Sensory analysis results showed that textural properties of Gaziantep cheese changed with salt concentration of the brine. © 1999 Society of Chemical Industry     

传统黄酒发酵醪的酸败及防止措施

引起传统黄酒发酵醪酸败的主要因素有：淋饭酒母质量差、麦曲质量差、浸米浆水酸度的影响、米质差、蒸饭质量差、投料配比不正确、前酵温度控制偏高或偏低、清洁卫生不好、后发酵后期气温的快速升高、原料不清洁等;防止发酵醪酸败的措施有：保持生产清洁卫生、提高麦曲和淋饭酒母质量、控制浸米工艺、采用优质原料、提高蒸饭质量、严格控制投料配比和发酵温度等工艺条件、协调三边发酵平衡。（孙悟）     

贮藏温度对栝楼籽油脂酸败的影响

通过依据国家相关标准测定不同贮藏温度下栝楼籽的酸价、脂肪酶活动度、过氧化值、TBA 值及VE 的保留率以研究贮藏温度对栝楼籽油脂酸败的影响。结果表明：温度是影响栝楼籽油脂酸败的重要因素。在0℃和5℃的低温条件下,能明显抑制栝楼籽的脂肪酶活动度,降低酸价,延缓过氧化值和TBA 值的升高,减少VE 的消耗,有效延缓栝楼籽的油脂酸败。     

Effect of a flax seed (Linum usitatissimum) soaking treatment on the frozen storage stability of mackerel (Scomber scombrus) fillets

The effect of a flax seed (Linum usitatissimum) soaking on the development of rancidity in frozen mackerel (Scomber scombrus) was studied. Fresh mackerel fillets were soaked in an aqueous flax seed extract for 20 min and then kept frozen (?20 °C) for up to 7 months. A parallel experiment with non‐soaked fillets was carried out under the same conditions. The development of rancidity was measured by biochemical (free fatty acids, peroxides, conjugated dienes and trienes, secondary oxidation products, fluorescent and browning compounds and lipoxygenase activity) and sensory (general aspect, odour and colour) analyses. An inhibitory effect of the soaking treatment on rancidity development was observed according to the peroxide content and the formation of fluorescence and browning. A lower lipoxygenase activity was detected at 1 month in the soaked fillets; after this, no differences were obtained between either type of sample, whose activities at month 7 were negligible. According to the sensory analyses, non‐soaked fillets had fair quality at 1 month and were rejectable at 3 months, while the soaked ones were still of good quality at 1 month and rejectable at 5 months. According to the present results, soaking in an aqueous flax seed extract could be useful for inhibiting the development of rancidity in fatty fish fillets. Copyright © 2006 Society of Chemical Industry     

Is It Advisable to Store Olive Oil in PET Bottles?

To assess the role of the container material on the quality of olive oil, literature results concerning the analytical definition of the quality of oils stored in PET or glass bottles were critically reviewed. The performance of active and passive barrier PET containers may move towards that of glass bottles. The influence of storage conditions was also considered: the main factors affecting the sensory quality loss upon storage are light and the initial oil oxygen concentration, aside from the bottle material. Further research needs are anticipated since new active and passive barrier bottles indeed deserve further attention.     

影响嗜酸耐热杆菌芽孢形成率的因素及不同防腐剂的抑菌效果

分析了嗜酸耐热芽孢杆菌污染的原因 ,研究了影响嗜酸耐热杆菌芽孢形成率的因素、温度和时间对果汁饮料的灭菌效果及不同防腐剂的抑菌效果