玉米醇溶蛋白阻湿性及抗氧化性应用的研究

对玉米醇溶蛋白在食品保鲜中的应用进行了研究。实验证明玉米醇溶蛋白具有良好的保湿性抗氧化性。采用玉米醇溶蛋白液作硬糖,可以延缓硬糖吸水溶化,防止硬糖发烊、返砂,以便长久地保持硬糖的质量,在玉米醇溶蛋白溶液中添加增塑剂能更有效地增强其保湿性。用玉米醇溶蛋白浸涂杏仁及核桃仁能延缓其氧化酸败速度,而添加增塑剂能使膜更好地粘着于食品表面,从而增强了膜的阻氧性。杏仁及核桃仁的最佳涂膜液配比为：在10ml10%玉米醇溶蛋白中加入0.8ml甘油、0.5ml虫胶.     

谷朊粉与玉米醇溶蛋白复合膜的制备及其在榛子仁保鲜中的应用

研究了谷朊粉与玉米醇溶蛋白可食性复合膜的最佳成膜条件,以及复合膜液涂膜处理对榛子仁的保鲜效果。结果表明:当玉米醇溶蛋白添加量25%,乙醇体积分数55%,甘油添加量20%,pH12时,复合膜的性能最佳。经复合膜液涂膜处理可显著抑制榛子仁的氧化酸败,保鲜效果优于谷朊粉单组分涂膜处理。在常温下保鲜100d后,经复合膜保鲜处理的榛子仁其感官质量良好。     

负载丁香酚/纳他霉素的玉米醇溶蛋白膜的制备、性能及其应用

以玉米醇溶蛋白、纳他霉素、丁香酚、甘油、乙醇为原料,采用流延法制备成负载丁香酚/纳他霉素的玉米醇溶蛋白膜,通过单因素实验对成膜工艺进行优化。并将负载丁香酚/纳他霉素的玉米醇溶蛋白膜涂膜于柑橘表面进行保鲜。结果表明:当玉米醇溶蛋白和80%乙醇固液比1∶10(g/mL),纳他霉素含量0.05%,丁香酚含量10ug/0.05%纳他霉素,甘油浓度为玉米醇溶蛋白的20%时,膜的拉伸强度7.6MPa,红外光谱图和差热分析图表明添加物没有改变玉米醇溶蛋白的主要结构且具有良好的相容性。柑橘表面涂膜保鲜实验结果表明,负载丁香酚/纳他霉素的玉米醇溶蛋白膜涂膜处理保鲜显著。     

增塑剂对玉米醇溶蛋白膜阻隔性能影响北大核心

玉米醇溶蛋白具有较好成膜性,但其形成膜较脆,需通过添加不同增塑剂加以改善;但添加增塑剂会使膜阻隔性能受到影响。该实验以甘油、聚乙二醇(PEG)400、单甘油酯为增塑剂,研究在不同乙醇浓度时制备玉米醇溶蛋白(zein)膜阻湿性及阻油性;结果表明,当乙醇浓度为80%、甘油添加量为0.3 g/g zein,PEG–400添加量为0.2 g/g zein,单甘油酯添加量为0.3 g/g zein时,膜的水蒸汽透过率最小,透油率最大。     

制备条件对玉米醇溶蛋白与小麦谷朊粉复合膜性能影响

该实验研究玉米醇溶蛋白添加量、增塑剂PEG400添加量、液固比、温度对由玉米醇溶蛋白与小麦谷朊粉制得复合膜性能影响。结果表明,复合膜断裂延伸率与抗拉强度分别在玉米醇溶蛋白添加量为20%和60%时达最大值;复合膜断裂延伸率和抗拉强度随PEG400添加量增加分别增大和减小;复合膜断裂延伸率在加热处理温度为60℃时达最大值,而抗拉强度随加热处理温度升高逐渐增大;复合膜断裂延伸率和抗拉强度在液固比为8∶1时分别达到最小值和最大值。     

玉米醇溶蛋白在冷却肉保鲜中的应用

以猪肉为代表,研究了玉米醇溶蛋白在冷却肉保鲜中的应用.以TVB-N值、pH、嗜冷菌总数和色差光学指标L*、a*、b*为考察指标.研究结果表明:玉米醇溶蛋白应用于冷却肉涂膜保鲜的效果较好,最佳的涂膜条件为8%玉米醇溶蛋白 0.02%植酸 0.20%柠檬酸的80%乙醇溶液.按照实验中的方法进行灭菌、涂膜后,4℃下贮存,冷却肉保鲜期达28d,各项指标仍符合国家鲜肉二级鲜度标准.     

黑豆皮多酚提取及其对草莓保鲜效果的影响

以乙醇为溶剂提取黑豆皮中的多酚类物质,将其与玉米醇溶蛋白混合制成可食性复合保鲜膜,考察复合膜对草莓的保鲜效果。结果表明:黑豆皮多酚的最佳提取条件为乙醇体积分数85%,提取时间4 h,水浴温度75℃,在该条件下多酚提取量为2.19 mg/g。添加多酚可以增强玉米醇溶蛋白可食性复合膜的保鲜效果,其中添加7%多酚的复合膜对草莓的保鲜效果最优,贮藏6 d时草莓的失重率和腐败率分别为0.43%、49.95%,显著优于对照组。     

羊肉涂膜保鲜工艺优化

以新鲜羊肉为原料,以玉米醇溶蛋白为成膜剂,以玉米须黄酮、沙棘叶多酚为复合涂膜保鲜剂,以色差值△Eab、菌落总数、pH值和挥发性盐基氮TVB-N值等为考察指标,通过单因素实验及正交实验,确定复合涂膜保鲜工艺。结果表明:成膜剂配比为1 g玉米醇溶蛋白:9 mL体积分数80%乙醇,添加0.1%的玉米须黄酮,0.2%沙棘叶多酚,成膜时间为5 min,在此条件下,鲜羊肉可在4℃保鲜25 d。     

可食性玉米醇溶蛋白膜的制备及其在食品保藏中的应用研究

研究了玉米醇溶蛋白膜的制备及其在食品保藏中的应用,以所提取的醇溶蛋白为原料,加入增塑剂,按一定的料液比加入乙醇溶解,然后进行流延成膜。对乙醇浓度、料液比及增塑剂对可食性薄膜性能的影响进行了研究,利用TA—XT2i质构仪对所得薄膜机械性能进行了测定,结果表明用90％的乙醇、料液比为10：1,添加40％油酸增塑,所得薄膜最佳,其抗拉强度、弹性、韧性分别为493．0g、3．12mm、261．34g·s。试验以荷兰瓜为研究鲜对象,考察了玉米醇溶蛋白膜的保鲜效果,结果表明玉米醇溶蛋白膜可减少果蔬的水分散失。     

玉米胚芽粕制备蛋白膜工艺优化及抗氧化研究

目的:利用玉米胚芽粕中的醇溶蛋白制备玉米醇溶蛋白膜,减少塑料膜对环境的污染。方法:以玉米胚芽粕为原料,通过碱溶酸沉从玉米胚芽粕中提取得到玉米醇溶蛋白,加入一定量的乙醇溶液再利用超声波辅助法加入适量的增塑剂和还原剂,在一定的水浴温度下水浴30 min,待膜液室温后,膜液流延成玉米醇溶蛋白膜。探究丙三醇添加量、超声时间、乙醇体积分数以及水浴温度4个因素对玉米醇溶蛋白膜的水溶性、水蒸气透过率、CO₂透过率的影响,得出最佳制备工艺,并通过将成膜液涂布在梨切片表面进行抗氧化保鲜试验,同时做涂膜空白对照,观察相同时间内梨切片表面的褐变程度。结果:通过正交试验,得到最优制膜工艺为丙三醇添加量0.3 g/g醇溶蛋白、超声时间5 min、乙醇体积分数80%、水浴温度70 ℃。在此条件下,玉米醇溶蛋白膜水溶性为19.75%、水蒸气透过率为6.13 g·mm/(m²·d·kPa)、CO₂透过率为0.21 g/(m²·h),玉米胚芽粕制备蛋白膜液能够使梨切片的褐变速度明显降低。结论:玉米胚芽粕制备蛋白膜可行,膜液能够在果蔬保鲜上起到很好的抗氧化效果。     

Studies on emulsion-type buffalo meat sausages incorporating skeletal and offal meat with different levels of pork fat

Ready-to-eat emulsion-type buffalo meat sausages were developed by using a combination of 80% meat components with 20% pork back fat. The meat components were constituted of 70 parts buffalo skeletal meat and 30 parts offal meat (rumen meat and heart meat in equal proportions). The emulsion stability, cooking losses of emulsions and sausages, composition of cooked sausages, eating quality of sausages and the microscopic characteristics of the raw emulsion and cooked sausages were studied. The light microscope micrograph of the raw emulsion showed uniformly well distributed fat globules embedded in a dense protein gel. The cooked emulsion also showed uniformly sized fat globules well distributed in a fine, compact, coagulated protein gel, which retained their original spherical shape. Good quality emulsion-type sausages could be produced having a high emulsion stability (0·87 ± 0·07 ml fat release/100 g emulsion); a low emulsion cooking loss (9·60 ± 0·60%) and a low sausage cooking loss (8·83 ± 0·48%). The overall acceptability of sausages was also high.     

Microbial contamination of carcasses, meat, and equipment from an Iberian pork cutting plant

An assessment and follow-up of the microbial contamination of an Iberian pork cutting room is presented. Samples were taken from carcasses (n = 76), meat pieces (three types, n = 71), meat for dry-cured sausages (3 types, n = 66), and surfaces of equipment (n = 158). Aerobic plate counts (APC) at 37 degrees C on meat pieces (primal cuts) were lower than on carcasses (3.62 log CFU/10 cm2 against 4.63 log CFU/10 cm2), probably owing to the removal of the skin. However, more than 80% of the meat pieces showed presence of Escherichia coli. For the three types of meat intended for dry-cured sausages, higher counts (P < 0.001) were found for meat type 3--an important cut obtained from the vertebral column--at 2.62 log CFU/g for E. coli; the particular surface used in the handling of meat type 3 also showed high counts (P < 0.001) for E. coli. Consequently, attention should be paid to the hazard analysis critical control point plan at this stage. Salmonella was isolated from 3.94% of the carcass surfaces (perianal zone), 4.46% of meat pieces, and 13.58% of meat for dry-cured sausages. Moreover, the percentages for isolation of Salmonella from carcasses of Iberian pigs (extensive rearing) in our study were lower than those generally reported in the literature for "white pigs" (intensive rearing). Coagulase-positive Staphylococcus aureus was isolated in 31.82% of meat samples for dry-cured sausages, in 16.90% of meat pieces, and in 15.50% of the equipment after 4 h of work. Of the coagulase-positive strains isolated, 47.61% were producers of enterotoxin.     

The use of hot salted chicken meat for processing

Frankfurter-type sausages and meat rolls were prepared from chicken broiler breast and leg muscles, the former from comminuted breast and leg muscles salted pre-rigor within 40 min, the latter from breast and leg muscles separately injected with brine 15 min after slaughter. Their properties were compared with those of similar products made from chilled meat.     

两个不同品种辣椒盐渍过程中细菌群落及品质变化研究

为探究辣椒盐渍过程细菌群落及品质变化,选取山东地区的金塔和艳红辣椒,监测了盐渍12周内样品细菌群落、可滴定酸、pH、水分含量、水分活度、氯化钠、还原糖、辣度、有机酸、核苷酸和氨基酸态氮11个指标。结果表明:两种辣椒盐渍第3周是细菌动态变化的拐点,在此之前,魏斯氏菌属、乳杆菌属等盐渍有益菌数量较多,在此之后肠杆菌属数量增加,可能由于两种辣椒的发酵程度不高,无法抑制肠杆菌的生长。两种辣椒盐渍第4周是品质与风味变化的拐点,在此之前还原糖、乳酸、乙酸、核苷酸和氨基酸态氮这些能赋予盐渍辣椒良好风味的物质含量较高,氯化钠含量适宜。因此,本研究中金塔与艳红盐渍辣椒的最适宜盐渍时间为3～4周。并且水分活度和水分含量决定了盐渍程度。金塔盐渍辣椒水分活度和水分含量分别稳定在0.80和69.3%左右,高于艳红盐渍辣椒的0.78和63.5%,因此推测金塔盐渍辣椒发酵程度更高。本研究为盐渍辣椒加工企业生产技术工艺优化提供数据与技术支持,为推进盐渍辣椒产品高质量发展提供理论支撑。     

玉米醇溶蛋白膜的制备及其保鲜效果评价

该实验制备了负载大蒜素-丁香酚的玉米醇溶蛋白膜,并评价其对圣女果的保鲜效果。研究表明大蒜素-丁香酚混合精油的加入量为1.50%时（体积分数）,所制得的玉米醇溶蛋白膜在外观、厚度、透明度等方面表现良好。用此配方对圣女果进行覆膜处理,负载大蒜素和丁香酚的蛋白膜与空白膜和对照相比,在贮藏期间圣女果的失重率、腐烂软化率、褐变度均小于空白对照组,在第8天各项指标分别较对照降低22.92%、50.00%、19.11%;圣女果的维生素C含量在第8天较对照提高1.69%,在第10天可溶性糖含量较对照提高9.58%。实验结果表明,负载大蒜素-丁香酚的玉米醇溶蛋白膜在减少圣女果水分流失、抑制腐烂和抗氧化等方面的性能均有了明显的提高,可以进一步开发成蔬果保鲜剂进行应用。     

Comparative studies on lipid oxidation of organic model sausage without nitrite produced with the addition of native or autoclaved mustard seed and acid whey

The objective of this work was to evaluate the influence of the addition of native and autoclaved mustard seed (AMS) with combination of acid whey (AW) on the stability of organic model sausages during 30 days of vacuum storage by measuring primary and secondary products of lipid oxidation, the changes in the fatty acid composition, oxidation–reduction potential and antioxidant capacity. Briefly, the addition of AW (5%) with combination of AMS (1%) significantly increased the capacity of sausages to capture the radical cations 2,2‐azinobis(3‐ethyl‐benzothiazoline)‐6‐sulphonate at 1 day of storage which suggests that autoclaved mustard possessed significantly higher amount of phenolic acids compared with native mustard. The salted samples with mustard seed addition characterised by lower oxidation–reduction potential values (264.5–302.1 mV) during the whole storage period compared with control‐cured sample (307.3–330.5 mV). Results of conjugated dienes (CD) measurements indicated that salted meat product samples with mustard seed addition were characterised by significantly lower CD concentration (1.12–1.90 μmol mg^?1 meat product) compared with control‐cured sample (1.86–2.55 μmol mg^?1 meat product). The AW and mustard seed added to uncured sausage were able to protect polyunsaturated fatty acids against the oxidation comparable to nitrite.     

Analysis of tomato and jalapeño and Serrano pepper imports into the United States from Mexico before and during a National Outbreak of Salmonella serotype Saintpaul infections in 2008

Case-control studies conducted during a multistate outbreak of Salmonella enterica serotype Saintpaul infections in 2008 revealed associations between illness and the consumption of jalape?o peppers, Serrano peppers, and tomatoes. Traceback investigations of implicated jalape?o and Serrano peppers led to farms in Tamaulipas and Nuevo León, Mexico. We conducted a novel analysis of a U.S. Food and Drug Administration database of tomatoes and jalape?o and Serrano peppers imported from Mexico during the first half of 2008 to describe the temporal and spatial flow of these items into the United States. Shipments of all three produce items followed a south-to-northwest corridor; 87% of peppers and 97% of tomatoes produced in Mexican states located west of the Sierra Madre Occidental were transported to ports in California and Arizona, and 90% of peppers and 100% of tomatoes produced in states east of the Sierra Madre Occidental were transported to ports east of Arizona. We found a significant correlation between state-specific infection rates and quantity of imported Mexican jalape?o and Serrano peppers to U.S. states by the first-level consignee but not for imported Mexican tomatoes. We localized production regions of interest by finding that quantities of both peppers and tomatoes imported from the states of Nuevo León and Tamaulipas were correlated with infection rates. In outbreaks possibly caused by agricultural commodities, analysis of import databases may foster a better understanding of growing seasons, harvest sites, shipment itineraries, and consignee destinations, thereby adding valuable insight into findings derived from epidemiologic studies.     

Effect of E-beam treatment on the bioaccessibility of folic acid incorporated to ready to eat meat products

Meat products are a potential matrix to fortify with folic acid (FA). In previous studies the effect of E-beam treatment on the stability of FA in ready to eat (RTE) meat products has been described. However, the FA bioaccessibility in both traditional and treated (3 kGy) RTE meat products has not yet been studied. We investigated the availability for intestinal absorption (bioaccessibility) of FA using a dynamic gastrointestinal model (TIM system). Three different types of meat products, hamburgers, cooked sausages and dry fermented sausages, initially fortified with 24 μg/g FA were tested as freshly prepared products and as RTE products. The bioaccessibility of FA during the passage through the TIM system was high for all three products, irrespective the E-beam treatment. From hamburgers the bioaccessibility was 82% and 100%, from cooked sausages, 61 and 79% and from dry fermented sausages 81 and 82%, with or without e-beam treatment, respectively.     

Antioxidant activities of different colored sweet bell peppers (Capsicum annuum L.)

ABSTRACT:  Antioxidant compounds and their antioxidant activity in 4 different colored (green, yellow, orange, and red) sweet bell peppers ( Capsicum annuum L.) were investigated. The total phenolics content of green, yellow, orange, and red peppers determined by the Folin-Ciocalteau method were 2.4, 3.3, 3.4, and 4.2 μmol catechin equivalent/g fresh weight, respectively. The red pepper had significantly higher total phenolics content than the green pepper. Among the 4 different colored peppers, red pepper contained a higher level of β-carotene (5.4 μg/g), capsanthin (8.0 μg/g), quercetin (34.0 μg/g), and luteolin (11.0 μg/g). The yellow pepper had the lowest β-carotene content (0.2 μg/g), while the green one had undetectable capsanthin and the lowest content of luteolin (2.0 μg/g). The free radical scavenging abilities of peppers determined by the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) method were lowest for the green pepper (2.1 μmol Trolox equivalent/g) but not significantly different from the other 3 peppers. All 4 colored peppers exhibited significant abilities in preventing the oxidation of cholesterol or docosahexaenoic acid (DHA) (C22:6) during heating. However, these 4 peppers did not show significant differences in their abilities in preventing cholesterol oxidation. The green pepper showed slightly higher capability in preventing the oxidation of DHA compared to the other 3 peppers.     

Usefulness of calcium lactate, citrate and gluconate for calcium enrichment of dry fermented sausages

Food manufacturers are interested in new ways to improve the nutritional value of their meat products. In this study, calcium lactate, gluconate and citrate have been added to dry fermented sausages in an attempt to determine whether they are useful for enriching these meat products with calcium. The sausages were manufactured with different amounts of pork backfat (6, 15, and 30%) and the salts were added in sufficient amounts to 100 g of sausage to give 20% and 30% of the recommended daily allowance (RDA) of calcium established by the Institute of Medicine of the USA (1000 mg/day). The lower concentration of whichever calcium salt (20% of RDA), was the most sensorially adequate. With this amount these sausages can be considered a “source of calcium”. In addition, we found that the lower backfat percentage (6%) compromises the acceptability of the product.