Co-Treatment of EFF and 1-MCP for Enhancing the Shelf-Life and Aroma Volatile Compounds of Oriental Sweet Melons(Cucumis melo var.makuwa Makino)

Compared to other melon types, oriental sweet melon （Cucumis melo var. makuwa Makino） is quite a different species with a shorter shelf-life due to its typical climacteric behavior and thin pericarp. The purpose of this experiment is to explore the effects of co- treatment of enhanced freshness formulation （EFF） and 1-methylcyclopropene （1-MCP） on physiological changes and the content of aroma volatile compounds introduced by them of two oriental sweet melon cultivars （Yumeiren and Tianbao） during storage. The melons were stored in incubators with temperature of 15~C and a relative humidity of 85% for 24 d during which fruit quality and related physiological index were measured. Compared to the control, both treatments delayed fruit weight loss rate and kept the fruit firmness, water content and soluble solids content. Ascorbate peroxidase （APX） and phenylalanine ammonia lyase （PAL） activities showed fluctuations in treated melons, while lipoxygenase （LOX） activity （P〈0.01） and malondialdehyde （MDA） content （P〈0.05） decreased compared to control. During the early stage of storage, alcohols and aldehydes were the main volatile compounds, and esters gradually increased during storage. Of all the esters, acetic esters were the main components, followed by oxalic acid esters and other esters. The total content of aroma volatile compounds, esters, alcohols and aldehydes of co-treated melons were all higher than those of 1-MCP treated and control melons. In addition, the aroma volatile peak of co-treated melons occurred later than that of 1-MCP treated and control melons. In summary, co-treatment of EFF and 1-MCP was more beneficial than 1-MCP treatment to delay ripening and senescence, maintain fruit quality, enhance shelf-life and improve levels of aroma volatile compounds.

Chitosan Extends the Shelf-life of Filleted Tilapia (Oreochromis niloticus) During Refrigerated Storage

Shelf-life extension of aquatic products is of significant economical importance. To determine the potential effect of chitosan on the shelf-life of filleted tilapia, this study analyzed the bacterial community diversity in fresh and spoiled tilapia fillets stored at (4 ± 1)℃ and examined the antimicrobial activity of chitosan against relevant bacteria isolates. Results showed that Pseudomonas (20%) and Aeromonas (16%) were abundant in fresh tilapia fillets, whereas Pseudomonas (52%), Aeromonas (32%) and Staphylococcus (12%) were dominant in the spoiled samples. Chitosan showed wide-spectrum antibacterial activity against bacteria isolated from tilapia and 5.0 g L-1 chitosan was selected for application in preservation. We further determined the shelf-life of chitosan-treated, filleted tilapia stored at (4 ± 1)℃ based on microbiological, biochemical and sensory analyses. Results showed that the shelf-life of chitosan-treated, filleted tilapia was extended to 12 d, whereas that of untreated, control samples was 6 d. These indicate that chitosan, as a natural preservative, has great application potential in the shelf-life extension of tilapia fillets.

Effect of Packaging Conditions on Shelf-Life of Mortadella Made with Citrus Fibre Washing Water and Thyme or Rosemary Essential Oil

The “elimination” of chemical additives used in a wide variety of foods is demanded, while “natural” additives are seen as a benefit for both quality and safety. Researchers are looking for new sources of ingredients and/or additives. The aim of this work was to study the effect of 1) the addition of 5.00% citrus fibre washing water (CFWW) and 0.02% rosemary essential oil (REO) or 0.02 % thyme essential oil (TEO) and 2) storage conditions on the chemical, microbe- ological and sensorial properties of mortadellas, a bologna-type sausage. CFWW + REO or CFWW + TEO samples stored in vacuum packaging showed the lowest TBA values. The resulting products were packed either in vacuum, modified atmosphere or air pouches and stored for 24 days. Lipid oxidation was assessed by the TBA method, while a quantitative descriptive analysis was carried out for sensory evaluation. Microbiological counts were also determined. CFWW + REO samples stored in vacuum packaging showed the lowest counts of aerobic and lactic acid bacteria. The sensory evaluation provided similar scores for CFWW + REO and CFWW + TEO samples. The lowest scores were obtained for control mortadella stored in air packaging. The addition of citrus fibre washing water and spice essential oils is a technologically viable alternative in emulsified meat products, since they improve customer acceptance and have desirable effects as regards oxidative stability and reduced microbial growth, which contributes to prolonging their shelf-life.

Sodium dehydroacetate treatment prolongs the shelf-life of'Kyoho'grape by regulating oxidative stress and DNA methylation

In this study,we tested the ability of sodium dehydroacetate(SD)to extend the shelf-life of‘Kyoho’grape.Among the different concentrations of SD tested(0,0.01,0.1 and 1.0 mmol L^(-1)),0.01 mmol L^(-1) SD was the most effective in prolonging the shelf-life of‘Kyoho’grape.Compared with the control,the weight loss rate,browning index and hydrogen peroxide(H_(2)O_(2))and malonaldehyde contents were significantly lower in the 0.01 mmol L^(-1) SD treatment,whereas the healthy berry rate,berry firmness,total soluble solids(TSS)content,ascorbic acid content and superoxide dismutase(SOD)activity were significantly higher.In addition,an analysis of‘Kyoho’grape DNA using methylation sensitive amplification polymorphism(MSAP)markers showed that the average DNA methylation level was significantly higher in the 0.01 mmol L^(-1) SD treatment than in the control.Together,these results indicate that 0.01 mmol L^(-1) SD could be used to extend the shelf-life of‘Kyoho’grape.Moreover,a strong connection between reactive oxygen species(ROS)metabolism and DNA methylation change during storage was revealed.

Effect of Post-Harvest Handling and Ripening Methods on Quality and Shelf-Life of Banana

Banana (Musa spp.) is a highly perishable fruit that requires special handling. In Eritrea, post-harvest handling practices are characterized to be poor and as a result, poor fruit quality and high post-harvest loss are common. Thus, the purpose of this study was to evaluate the effect of different post-harvest handling and ripening methods on quality and shelf-life of banana. A Complete Randomized Design (CRD) was used for evaluating a combination of two levels of post-harvest handling and four ripening methods in a factorial combination conducted in the laboratory of Horticulture at Hamelmalo Agricultural College. Peel colour change, physiological weight loss, pulp to peel ratio, total soluble solids (TSS), pulp pH, ripening period and shelf life were parameters studied. The results showed fruits treated with ripened tomato showed improved characteristics in all parameters compared to those treated with smoke from kerosene burning or mixed with moringa leaf. Similarly, fruits brought directly from the farm were better than those collected from the ripening room after passing the conventional post-harvest handling. Based on the results of this study, it can be concluded that ripening of banana with the help of tomato improves fruit quality and shelf life. Thus, it can be a safe and better alternative to smoking from kerosene burning. While moringa leaf has no potential as an alternative.

A Time Dependent Inventory Model for Exponential Demand Rate with Constant Production Where Shelf-Life of the Product Is Finite

In this paper a time dependent inventory model is developed on the basis of constant production rate and market demands which are exponentially decreasing. It advances in quest of total average optimum cost considering those products which have finite shelf-life. The model also considers the small amount of decay. Without having any sort of backlogs, production starts. Reaching at the desired level of inventories, it stops production. After that due to demands along with the deterioration of the items it initiates its depletion and after certain periods the inventory gets zero. The decay of the products is level dependent. The objective of this paper is to find out the optimum inventory cost and optimum time cycle. The model has also been justified with proving the convex property and by giving a numerical example.

超高压处理对鲜榨复配果汁品质及货架期的影响

为使经杀菌处理后果汁的活性成分和风味物质更接近原鲜榨果汁,本研究以猕猴桃、菠萝、芒果为原料制备复配果汁,对比超高压处理与热处理(85℃、5 min)两种杀菌方式对鲜榨复配果汁品质及货架期的影响。结果表明:复配果汁比例V菠萝原浆:V猕猴桃原浆:V芒果原浆=4:2:4时,与传统热处理相比,在450 MPa、25℃、15 min超高压条件下处理,pH、b^(*)值、可溶性固形物无明显差异(P>0.05),维生素C含量损失减少12.1%、多酚含量损失减少17.5%,品质更接近于未处理果汁;通过对复配果汁主要挥发性成分进行分析,烯类、酯类、醇类、酮类、醛类等风味物质的损失显著小于(P<0.05)热处理,且蒸煮味物质糠醛没有生成,丙酮和1-辛烯-3-酮相对含量分别减少68.4%、41.4%;菌落总数、霉菌和酵母菌杀菌效果均符合饮料现行有效卫生标准;通过Q_(10)模型对货架期进行预测,在4℃条件下储藏,其货架期可达到103 d。综上,超高压处理鲜榨复配果汁在有效杀灭微生物的同时更利于复配果汁保持天然品质及其货架期。

临期盒装豆腐腐败菌鉴定及抑菌效果评价

【目的】探究临期盒装豆腐优势腐败菌及对其抑制效果,延长盒装豆腐货架期。【方法】以临期盒装老豆腐和内酯豆腐为研究对象,分离优势腐败菌,并通过16S rDNA全序列分析法对腐败菌进行鉴定。分别添加不同质量浓度的山梨酸钾、脱氢乙酸钠、乳酸链球菌素单一组及3种防腐剂的复配组到样品中,采用加速试验,以抑菌率为指标,通过响应面法确定最佳复配防腐剂配方和质量浓度。【结果】临期盒装豆腐中的优势腐败菌为植生拉乌尔菌(Raoultella planticola)和沃纳利葡萄球菌(Staphylococcus warneri)。单一防腐剂的抑菌率随质量浓度的增加而增加,而复配防腐剂的抑菌效果更好。当山梨酸钾为0.21 g·L^(-1)、脱氢乙酸钠为0.15 g·L^(-1)、乳酸链球菌素为0.17 g·L^(-1)时,对植生拉乌尔菌的抑菌率最高,为25.48%;当山梨酸钾为0.36 g·L^(-1)、脱氢乙酸钠为0.11 g·L^(-1)、乳酸链球菌素为0.10 g·L^(-1)时,对沃纳利葡萄球菌的抑菌率最高,为32.07%;当山梨酸钾为0.29 g·L^(-1)、脱氢乙酸钠为0.03 g·L^(-1)、乳酸链球菌素为0.01 g·L^(-1)时,该复配防腐剂对2种腐败菌均有较好的抑菌效果,抑菌率分别为25.17%和32.42%;将该复配防腐剂添加到回接腐败菌的盒装豆腐中,并于37℃下进行储藏,处理后的盒装豆腐货架期相应延长2 d,经测算相当于在0~4℃下货架期延长7 d。【结论】在加速试验条件下,复配防腐剂可以有效抑制临期盒装豆腐中优势腐败菌,延长货架期。

采前氯化钙和水杨酸处理对蟠枣采后贮藏品质的影响

为探究采前处理对蟠枣果实采后贮藏品质的影响,以新疆主栽鲜食品种蟠枣为研究对象,分别于果实花期、幼果期、膨大期、着色期采用清水(CK)、10 g/L氯化钙(CaCl_(2))、100 mmol/L水杨酸(SA)和10 g/L CaCl_(2)+100 mmol/L SA进行采前喷施处理,采收后置于常温货架贮藏,每天统计果实的转红率、转红指数、腐烂率和失重率,测定果实的可溶性固形物含量、硬度和色泽等指标。结果表明:采前喷施CaCl_(2)、SA和CaCl_(2)+SA均可一定程度上抑制蟠枣的转红和腐烂,使其保持较低的失重率,使果实维持较高的可溶性固形物含量和硬度,保持较好的色泽,其中,10 g/L CaCl_(2)+100 mmol/L SA采前处理效果最佳,常温货架8 d时,果实的转红率和腐烂率分别较对照低23.34个百分点和36.66个百分点,失重率仅为1.68%,果实可溶性固形物含量维持在21.47%,硬度为9.45 kg/cm^(2),保持较好的商品性。综上,采前喷施10 g/L CaCl_(2)+100 mmol/L SA能有效保持蟠枣采后贮藏品质。

复合蔬菜汁部分替代亚硝酸盐对鲜烧鸡保质期的影响

文章主要研究了复配的天然蔬菜汁部分替代亚硝酸盐对鲜烧鸡保质期的影响。以挥发性盐基氮(TVB-N)值、pH值和色差值等指标进行单因素试验,确定各因素的最佳范围;在单因素试验的基础上选择3个水平进行正交试验,得出复合蔬菜汁的最佳配比。结果表明,蔬菜汁添加量在10%~20%之间,胡萝卜汁、芹菜汁和亚硝酸盐的配比为10%胡萝卜汁+20%芹菜汁+0.005%亚硝酸盐时,防腐效果最佳。在常温贮存8 d后,鲜烧鸡的色泽、感官品质较对照组有明显差异。此时烧鸡的TVB-N值为13.085 1 mg/100 g,硫代巴比妥酸(TBA)值为0.377 6 mg/kg,亚硝酸盐残留量为8.542 mg/kg,均低于国家标准。结果表明,利用天然蔬菜汁部分替代亚硝酸盐在传统肉制品中应用,加工方式绿色健康,具有广阔的前景。

陈皮牛肉预制菜品质的研究

预制菜是采用各种食材配以辅料,依据现代化标准加工制作而成的成品或半成品,经简易处理便可食用。将传统菜肴陈皮牛肉制作成预制菜不仅能适应当前社会发展的需要,而且能丰富现有预制菜的种类,对预制菜的长远发展具有重要意义。为探究陈皮牛肉预制菜的可行性,文章通过感官评价、脂肪氧化程度、质构、挥发性风味成分等研究陈皮牛肉预制菜的不同包装方式、储存方式、货架期及品质。结果表明,陈皮牛肉预制菜在料液混合包装方式下冷冻保存3 d时感官评价最佳,脂肪氧化程度低,保持较高的食用品质,在此条件下测得其风味物质种类繁多,主要包括醛类、酯类、酮类、醇类、烯烃类等化合物,硫代巴比妥酸反应物值接近于1.0 mg/kg,预制菜的质构等品质接近于传统陈皮牛肉菜肴。

基于低场核磁共振的预包装即食牛肉保质期预测模型研究

目的:开展预包装即食牛肉保质期快速、准确和无损的预测方法研究,对于保障产品货架期安全具有重要意义。方法:以预包装即食牛肉为分析对象,采集样品低场核磁H质子的T2弛豫时间,建立即食牛肉水分含量定量分析模型,结合样品感官接受性等建立预包装即食牛肉保质期预测模型。结果:预包装即食牛肉低场核磁谱图横向弛豫时间可较好地反映出随着贮存时间的延长航天即食牛肉的品质变化。建立了即食牛肉含水量预测模型,模型的预测误差小于4%;建模集相关系数(r)为0.9405,校正标准差(RMSECV)为34.5,相对分析误差(RPD)为3.1,对10个分别贮存一定时间但未参与建模的样本分别进行距离货架期终点的预测,预测结果与实测值的的相关性达0.99,预测结果的误差范围为0.7%~9.9%,RMSEP为13.6,预测模型的精确度满足货架期预测的精度要求。结论:低场核磁共振技术在预包装即食牛肉产品保质期预测方面具有应用潜力。

食用菌预制菜的工艺配方研究及保质期预测

为丰富食用菌预制菜产品种类并解决预制菜储藏和运输的问题,通过运用高温反压式杀菌技术和加速破坏性试验(accelerated shelf-life testing,ASLT),开发出了一种复配型食用菌预制菜配方,并预测了其常温储藏保质期。采用3种食用菌为主要原料制作食用菌配方预制菜,加入猪五花肉、胡萝卜等配料,通过单因素和正交试验优化了其配方组成,获得了感官接受度较高的配方。配方组成为杏鲍菇200 g、香菇150 g、黑木耳50 g、猪五花肉70 g、胡萝卜30 g、香辣酱15 g、食盐1.2 g、蚝油1 g。该配方产品通过真空包装、高温反压式杀菌(121℃,20 min)和加速破坏性试验,预测在20℃下的保质期为195.4 d,满足常温储藏要求。通过对食用菌预制菜生产工艺的研究,证明了常温储藏食用菌预制菜的可行性。

《血液储存标准》修订的思考与启示

国家卫生健康委员会新近正式批准发布的卫生行业标准WS 399-2023《血液储存标准》是WS 399-2012《血液储存要求》的最新修订版本,主要规定了全血、红细胞、血小板、粒细胞、血浆、辐照血等的储存要求,适用于采供血机构和医疗机构,是安全用血的基础和保障。

不同包装方式对番茄货架期品质的影响

为研究不同包装方式对番茄货架期品质的影响,以京采8号番茄品种为研究对象,选取红熟中期的果实,分别采用PE保鲜膜、PP防雾保鲜袋、PVC保鲜袋和PET保鲜盒包装,以不包装作为对照(CK),置于12℃条件下,通过测定可溶性固形物、可溶性糖、可滴定酸含量,以及色泽、硬度、感官品质、失重率和腐烂率等指标,确定适宜的包装方式。结果表明,包装处理有利于维持番茄货架期品质,不同包装方式在减轻可溶性固形物流失、减少固酸比波动、延缓感官品质劣变、降低失重率等方面无显著差异;PP防雾保鲜袋和PET保鲜盒在减轻可溶性糖、可滴定酸流失,延缓果实软化,降低腐烂率方面作用明显,货架期可达12 d;PVC保鲜袋在延缓果实转色、软化方面作用突出,适宜的货架期为10 d。

新型包装材料对甜玉米贮藏品质的影响

甜玉米采后代谢旺盛,品质极易发生劣变,包装保鲜为最简单的解决方式。为明确包装材料对甜玉米贮藏品质的影响,以“BM380”甜玉米为试验材料,研究采用7种材料包装的甜玉米在2~5℃贮藏条件下的失重率、感官品质、可溶性糖含量和VC含量的变化,并以感官品质为最主要指标判断包装材料的保鲜效果。结果表明:在7种包装材料中,欧乐甜玉米保鲜袋在降低甜玉米失重率方面表现最优,在贮藏14 d时失重率仅0.746%;生物气调保鲜包装袋包装的甜玉米在超市冷链销售保鲜期最长,可达7d,比对照超市聚乙烯包装袋延长4d,贮藏16d时感官指数为3.01,仍具食用价值,其次是欧乐甜玉米保鲜袋包装,甜玉米超市冷链销售保鲜期为6 d,贮藏13 d时感官指数为4.33,仍具食用价值;复命锁鲜袋可以维持甜玉米的VC含量,贮藏12d的VC含量较对照显著提高46.8%,其次是欧乐甜玉米保鲜袋包装,贮藏12、15d分别较对照显著提高38.03%、11.32%;加厚(抗菌/保鲜)膜自制包装袋包装的甜玉米可溶性糖含量下降最缓慢,贮藏15 d的可溶性糖含量比对照显著提高73.11%,欧乐甜玉米保鲜袋包装较对照显著提高49.09%。可见,欧乐甜玉米保鲜袋可减缓甜玉米失重,生物气调保鲜包装袋的冷链保鲜期较长,复命锁鲜袋可维持甜玉米的VC含量,加厚(抗菌/保鲜)膜自制包装袋可保持甜玉米的可溶性糖含量。综合考虑失重率、感官指数及营养成分损失情况,建议选择欧乐甜玉米保鲜袋。