High voltage atmospheric cold plasma technology as a food safety intervention for decontamination of cutting tools during ready-to-eat poultry meat slicing

This study aimed to build a prototype that integrates a cold plasma capability into a manual meat slicer while it is in operation to minimize cross-contamination from the circular cutting blade. A high voltage atmospheric cold plasma (HVACP) generator was attached to a meat slicer with a rotating 22.5-cm diameter stainless steel slicing blade. The meat slicer with the installed cold plasma generator was contained within a sealed, clear acrylic box. Listeria innocua (LI) was selected as the test organism, and initial testing was performed on stainless-steel coupons in room air at a relative humidity ranging from 30 to 90% for treatment times up to 240 s. Results found that 240 s and 90% RH showed a 3.0-log reduction of LI. These conditions were then replicated using “dirty” stainless-steel knife while rotating. The results showed only a 0.5-log LI reduction. The gas was changed from air to MA65 gas blend (65% O₂, 30% CO₂ and 5% N₂) and then a 1.91 log LI reduction was achieved on the “dirty” knife.Industrial relevanceDue to the rapid processing speeds required in the food industry, it is difficult to assure the complete cleanliness of the tools and surfaces used at all times, and then, operations like the cutting /slicing step are still one of the critical points for cross-contamination during meat processing. High voltage atmospheric cold plasma (HVACP) is a practical intervention that has the potential to deliver a continuous, in-situ decontamination of the knife during operation to mitigate the risk of cross-contamination. The developed prototype, as shown in this study, can deliver beneficial results in short treatment time and with minimal inputs of air and electricity, without heating effects, minimizing the use of water, or the use of sanitizers.     

不同采后处理对云南油桃和水蜜桃的贮藏保鲜效果对比

为探索延长云南油桃和水蜜桃保鲜期的方法,以云南文山黄金油桃和红蜜桃为试材,研究了1-MCP、ClO2、2种涂膜处理对黄金油桃和红蜜桃两种桃贮藏保鲜效果,结果表明:虽然1-MCP处理对两种桃L*、a*值和b*值的维持均有效果,但云南黄金油桃和红蜜桃适宜的采后处理方法不同;1-MCP处理的黄金油桃色差值最高,贮藏25d,L*、a*值和b*均维持较高,相对电导率值最低(54.43%),质量损失率较低(1.05%),TSS含量为16.27%最高,表明1-MCP处理是较适宜黄金油桃贮藏保鲜的处理。ClO2处理有利于红蜜桃外观的维持,贮藏25 da*值和b*值均高于其他处理,且具有最低的质量损失率和最高的TSS含量,相对电导率值为55.81%,低于1-MCP处理;表明ClO2处理是较适宜红蜜桃的采后处理。     

One-step bio-extraction of chitin from shrimp shells by successive co-fermentation using Bacillus subtilis and Lactobacillus plantarum

Chitin was bio-extracted in one-step from shrimp shells by successive co-fermentation using Bacillus subtilis and Lactobacillus plantarum in this study. To construct this co-fermentation system, B. subtilis was first cultured for 3 days for deproteinization (DP), and then L. plantarum was inoculated for demineralization (DM). After 6 days of co-fermentation, the final DP and DM efficiency reached 94.1% and 96.3%, respectively. The molecular weight, degree of acetylation, and crystalline index of chitin were reduced by 9.8, 5.6 and 1.4% with the DP time of 2 days extending to 3 days. Meanwhile, L. plantarum instead of B. subtilis became the dominant bacterium on day 5 of co-fermentation, with L. plantarum count of 6.19 log CFU/mL and lactic acid concentration of 28.22 g/L, respectively. The chitin prepared in this study exhibited similar structural characterization as commercial chitin. One step successive co-fermentation was a simple and feasible approach for high-quality chitin preparation.Industrial relevance: This study establishes one-step bio-extraction of chitin from shrimp shells by successive co-fermentation using B. subtilis followed by L. plantarum. One-step successive co-fermentation simplifies the intermediate processes of conventional two-step fermentation for extracting chitin. DP and DM happen during the entire co-fermentation period, which helps to achieve satisfactory DP and DM efficiency. This innovative yet simple method provides more possibilities for the biotechnological production of chitin on an industrial scale.     

不同外源补充对西兰花采后贮藏品质的影响

为探索外源补充对采后西兰花保鲜的作用效果,本文以清水为对照,分别采用200 mg/L赤霉素（GA）、200 mg/L赤霉素（GA）+无机盐营养液、50 mg/L 6-苄基腺嘌呤（6-BA）、无机盐营养液、50 mg/L 6-苄基腺嘌呤（6-BA）+无机盐营养液等5种处理,通过对西兰花贮藏期外观（色差）、营养物质（维生素C、可溶性固形物、叶绿素、水分活度）及其他生理生化指标（质量损失率、相对电导率、丙二醛含量）的比较分析,结果表明：与CK相比,西兰花采后外源补充可以有效抑制质量损失率、延缓相对电导率和丙二醛含量的上升,抑制叶绿素降解,有利于西兰花采后保持较高的水分、维生素C含量和可溶性固形物含量。200 mg/L赤霉素+无机盐营养液处理的西兰花,贮藏28 d时维持最高的TSS含量（7.27%）和Vc含量（27.53 mg/100 g Fw）,较高的叶绿素含量 （5.57 mg/100g Fw）,最低的MDA（15.31 nmol/g Fw）,是5种外源补充中最好的西兰花采后保鲜方法。     

莲藕片汽蒸加工工艺及其挥发性风味物质变化研究

以莲藕为对象,采用汽蒸加工方式处理制成食用莲藕片。在单因素实验基础上,通过正交试验优化,探讨莲藕片汽蒸最佳加工工艺。并采用固相微萃取-气质联用技术,分析汽蒸加工处理过程前后挥发性风味物质变化。结果表明:在电磁炉功率为1400 W、莲藕切片厚度为4 mm的条件下汽蒸16 min,汽蒸莲藕片的感官评分为89.08,色差为9.85,硬度为555.57 g,此时莲藕片呈淡黄色,藕片肉质脆嫩,咀嚼性较好,具有藕香味。SPME-GC-MS鉴定出新鲜、汽蒸莲藕片中的挥发性风味物质分别为45、42种,二者共有28种化合物。莲藕中主要风味物质有壬醛、癸醛等醛类物质,此外还有柠檬烯、棕榈酸乙酯、辛醇、1-壬醇、香叶基丙酮等,这些风味物质使莲藕片呈现不同的风味特征。经过汽蒸过程后,醛类、杂环类及含氮化合物相对含量增加,酯类、醇类、酚类和酸类含量减少,酮类、醚类、烃类含量无明显变化。该研究结果可以为莲藕挥发性风味分析及莲藕加工工业提供一定的理论依据。     

不同脱涩处理对中田大山楂采后贮藏品质的影响

为研究不同脱涩处理对中田大山楂采后贮藏品质及脱涩效果的影响。以清水浸泡+20 ℃恒温贮藏为对照组,以40%酒精溶液浸泡+30 ℃恒温贮藏、0.25%乙烯利溶液浸泡+30 ℃恒温贮藏和清水浸泡+30 ℃恒温贮藏为3个不同的处理组,通过测定中田大山楂硬度、可溶性固形物、可滴定酸、总糖、类黄酮、单宁含量等指标的变化来分析山楂采后贮藏品质的变化。结果表明: 不同脱涩处理中,40%酒精溶液浸泡+30 ℃恒温贮藏处理在不明显破坏山楂果实贮藏品质的条件下（硬度、可溶性固形物和可滴定酸等变化虽然快于对照组,但显著慢于其他两个处理组）,加速了果实中可溶性单宁向不可溶性单宁转化且效果最明显（15 d可溶性单宁含量显著低于对照组（P<0.05）,为对照组的9.5%）,进而达到良好的脱涩效果,为乙醇脱涩在水果加工中提供了良好的应用前景;相关性分析中,单宁与硬度、可滴定酸和可溶性固形物呈极显著正相关（P<0.01）,与总糖、固酸比、糖酸比呈极显著负相关（P<0.01）,与类黄酮呈显著负相关（P<0.05）,说明实验设计中的指标不仅可以反映山楂的贮藏品质,也可在一定程度上从侧面反映山楂可溶性单宁的变化。主成分分析中,40%酒精溶液浸泡+30 ℃恒温贮藏处理组,脱涩效果最佳。     

热泵干燥温度对柿子片干燥特性及品质的影响

目的:探明热泵干燥温度对柿子片干燥特性和品质的影响。方法:以柿子为原料,研究干燥温度对柿子片干燥时间、干燥速率,以及干制品色泽、硬度、复水率、单宁、总糖、维生素C和总酸的影响。结果:当热泵干燥温度为65℃时,柿子片干燥速度快,干燥时间短,此时干燥产品色泽鲜艳,与鲜果色泽相近,复水性能好,硬度最低,口感最好,总酸和维生素C含量最高,总糖等营养成分含量适中。结论:柿子片的最适热泵干燥温度为65℃。     

百香果果皮多糖提取工艺优化及其抗氧化活性研究

本文研究百香果果皮多糖的提取工艺条件及果皮多糖体外抗氧化活性。采用超声波提取方法,以百香果果皮多糖得率为响应值,在单因素实验基础上,优化液料比、超声功率、超声时间、超声温度等条件,得到最佳提取工艺:液料比为49:1(mL/g),超声温度69℃,超声时间15 min,超声功率105 W,多糖平均得率为5.890%,与预测值(6.09%)接近。体外抗氧化活性分析结果表明:当多糖浓度为2 mg/mL时,多糖对DPPH和羟自由基的清除能力分别为32.8%和59.0%,还原能力吸光值为0.34,较维生素C弱。研究成果将为百香果皮多糖的进一步研究及新产品开发提供理论指导。     

响应面优化仙草微波间歇-热风联合干燥工艺及其对仙草凝胶品质的影响

以仙草为研究对象,采用微波间歇-热风联合干燥方式,探讨微波功率、微波间歇时间、联合干燥转换点含水率及热风干燥温度对仙草多糖提取率的影响,采用Box-Behnken进行优化,并比较不同干燥方式处理仙草对其多糖提取率及凝胶品质的影响.结果表明,通过响应面优化试验获得最优工艺为微波功率为403 W,微波间歇时间为60 s,转...