‘印度青’苹果合成与分解代谢通量研究及贮藏温度的优化

本研究以‘印度青’苹果为原料,研究在不同贮藏温度下合成与分解代谢网络通量,并在此基础上优化其贮藏温度。将‘印度青’苹果放置在7 个不同温度（0、2、5、10、15、20、40 ℃）条件下,测定‘印度青’苹果不同部位糖酵解途径、三羧酸循环、蔗糖合成途径、磷酸戊糖途径的代谢通量。结果显示：2 ℃时蔗糖有较高的合成通量,由外到内4 个部位分别为32、42、47和33,乳酸盐也在2 ℃时有较高的代谢通量,由外到内4 个部位分别为1.87、1.86、1.86和1.86,在此温度下有较低的分解代谢和较高的蔗糖合成代谢,因此,2 ℃是‘印度青’苹果较好的贮藏温度。通过不同温度下‘印度青’苹果的各个部位之间代谢通量上的变化,可以建立以乳酸盐与蔗糖通量为评价标准的定量化模型,这可为今后更好地研究延长水果的贮藏寿命提供新的研究方法和理论参考。     

Polycyclic aromatic hydrocarbons in diet: Concern for public health

BackgroundExposure to carcinogenic compounds such as polycyclic aromatic hydrocarbons (PAHs) is responsible for numerous human health problems. Diet has been found responsible for nearly 88–98% exposure to PAHs in humans. Different studies have been conducted worldwide to investigate the role of food processing techniques and food matrix in PAHs' formation and adsorption, which has helped in establishing regulations and guidelines.Scope and approachThe present review focuses on the published research articles on concentrations and profile of PAHs in Indian food products. The levels in Indian diet were compared with those reported for similar food products and categories in international studies, and the associated gaps and future prospects were discussed. This paper holds importance for public health especially for societies having an Indian-influenced diet.Key findings and conclusionsIndian food products belonging to Beverages, Oils, Fruits, Vegetables, Supplements, Chocolates, Traditional items and Marine foods category accumulated PAHs during pre- and post-harvest stages and acted as the main sources of PAHs' exposure to humans. Compared to worldwide studies, studies focusing on PAHs in Indian food products are very few, basic in nature and limited in scope.     

荠菜总黄酮提取工艺的研究

研究了芥菜总黄酮的提取工艺.采用单因素实验,以芦丁为标准品用吸光光度法测定提取样品中黄酮含量.发现乙醇浓度、提取温度、提取液酸碱度以及芥菜的新鲜度对总黄酮的提取有影响.新鲜或烘干的荠菜用75%的乙醇溶液,加入4%的NaOH,在80℃下提取总黄酮为最理想的条件.     

A simple wheat germ diet for studying the nutrient requirements of the Indian meal moth, Plodia interpunctella (Hübner)

Indian meal moth infestation of processed cereal products during storage could be managed with little or no use of conventional pesticides if there was a greater recognition and use of the moth's innate vulnerabilities. Slowing the growth rate of the infesting larvae is a simple strategy that can decrease the amount of damage and decrease the frequency of pesticide intervention. The growth rates of Indian meal moths on different cereal products varies widely indicating product-related differences in nutrient availability for the insects. Nutrient availability depends upon both the amounts of nutrients available in the cereal product and upon physical characteristics of the product that restrict the assimilation of nutrients.

The development of control strategies for protecting processed cereal products based upon nutrient availability requires a simple, palatable test diet of known composition. Wheat germ mixed with 30% glycerol (w/w) provides a suitable growth medium for the Indian meal moth whose nutrients have been largely identified and quantified. Our studies indicate that dietary glycerol augments Indian meal moth growth and development on wheat germ by moisturizing the diet and probably provides a source of carbon and energy for larval growth.     

预制菜肴中芥菜护色及保脆工艺优化

为改善以芥菜为原料的预制菜肴在加工贮藏过程中易发生褐变和组织软化等问题,该研究以多酚氧化酶（Polyphenol Oxidase,PPO）活性、过氧化物酶（Peroxldase,POD）活性、叶绿素含量、剪切力、色差、维生素C为指标,通过单因素及正交试验设计分析不同漂烫条件以及不同种类和添加量的护色剂、保脆剂对芥菜品质的影响。结果表明,最佳工艺条件为：90 ℃漂烫2 min,抗坏血酸添加量0.06%（m/m）,柠檬酸添加量0.12%（m/m）,植酸添加量0.012%（m/m）,护色40 min,氯化钙添加量0.24%（m/m）,保脆30 min。在此工艺条件下,PPO和POD失活率分别达到了90.40%和66.03%,叶绿素含量最高为93.60 mg/100 g;在18 d贮藏期后,经此工艺处理后的芥菜与空白组相比,Vc含量,叶绿素含量,a*值绝对值和剪切力分别提升了333.65%,783.69%,158.23%和318.84%,得到的芥菜色泽自然、口感脆嫩,感官评分最高。此工艺能有效维持芥菜绿色色泽和脆嫩口感,为预制菜肴中其他绿叶蔬菜提供工艺参考。     

过硫酸氢钾复合盐在印度发漂白工艺中的应用

采用过硫酸氢钾复合盐复合过氧化氢对印度发进行漂白,考察过硫酸氢钾复合盐质量浓度、pH、时间、温度对印度发白度和断裂强力的影响。结果表明:过硫酸氢钾复合盐复合过氧化氢的漂白效果较传统过氧化氢漂白有了很大的提升,白度和断裂强力明显提高。     

Comparative study of the polypeptide profiles and functional properties of Sinapis alba and Brassica juncea seed meals and protein concentrates

Defatted meals and protein concentrates from six accessions of Sinapis alba and one accession of Brassica juncea mustard seeds were analysed for their polypeptide profile and functional properties. Two types of protein concentrates were prepared using acid‐induced and calcium‐induced protein precipitations. Meals from the S alba seeds had similar polypeptide composition, which was different from that of the B juncea meal. Non‐reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that two of the major polypeptides (50 and 55 kDa) in S alba seeds were susceptible to acid‐induced precipitation but resistant to calcium‐induced precipitation. The B juncea meal proteins were significantly (p ≤ 0.05) more susceptible to heat coagulation than the S alba meal proteins. Emulsifying activity index was significantly higher (p ≤ 0.05) in the B juncea meal and protein concentrates when compared with similar products from S alba. It was concluded that the presence of a high‐molecular‐weight (135 kDa) disulfide‐bonded polypeptide could have contributed to the lower emulsifying power of the S alba products when compared with the B juncea proteins that do not have this polypeptide. Copyright © 2005 Society of Chemical Industry     

Supercooling point variability in the Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

Factors affecting the supercooling point (SCP) of the Indian meal moth, Plodia interpunctella (Hübner), were investigated under various conditions. The effects of geographic origin, time under laboratory conditions, laboratory diet, stage of development, age within stage, and season on P. interpunctella SCP were examined. Overall, SCPs ranged from −28.6 to −2.4 °C. At the times of collection, differences in SCP between field-collected individuals and individuals from laboratory sources were negligible. The minimum observed SCP for most of the cultures tested soon after collection was below −20 °C. After 7 months under laboratory conditions, the mean SCP of field-collected and laboratory-reared cultures remained unchanged. No particular trend in SCP was observed when comparing cultures from northern and southern regions. Differences in laboratory diets did not affect mean SCP. Mean SCP for 1- and 4-d-old eggs was similar. Eggs (−24.4 °C), first instars (−23.5 °C), pupae (−22.2 °C), and adults (−22.4 °C) had lower mean SCPs than later instar larvae (−14.4 to −11.6 °C). When confined in the laboratory for 8 months under conditions which were not controlled, monthly mean SCP for the same culture varied by as much as 5.7 °C. Plodia interpunctella appeared to regulate its SCP as the season changed, with a relatively high mean SCP during summer and a marked decline of more than 10 °C in fall. The SCPs obtained in this study suggest that very low temperatures may be needed for disinfestation of P. interpunctella at all stages of development.     

Iodine content in bread,milk and the retention of inherent iodine in commonly used Indian recipes

Iodine deficiency disorders (IDD) is still a major public health problem and iodized salt remains the most effective means to control IDD in India. Few reports indicate that vegans have inadequate iodine intake while at the same time concerns are being raised on the implementation of universal salt iodization in the country. Therefore, we investigated the iodine content in bread, milk and commonly used Indian recipes prepared without iodized salt and the retention of inherent iodine therein. Results showed considerable iodine content in bread (25 μg/100 g) and milk (303 μg/L) as a positive fallout of universal salt iodization. Iodine content in 38 vegetarian recipes prepared without iodized salt was very low (2.9 ± 2.4 μg/100 g). Retention of inherent iodine (65.6 ± 15.4%) and iodine from iodized salt (76.7 ± 10.3%) in the same recipes was comparable. Thus, universal salt iodization programme remains the single most important source of dietary iodine for the Indian population.