Effects of Fungicide Treatments and Storage Temperatures on Fruit Quality of Two Mango （Mangifera indica） Cultivars

Harvested fruits of mango （Mangifera indica） suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigate the effects of fungicide treatments and storage temperatures on fruit quality of two mango cultivars, Keirt and Palmer. Mango fruits were treated with 0.04% or 0.08% v/v Triadimefon at either 53 ℃ （hot） or at room temperature and then either stored under ambient conditions （27-29 ℃） or in a refrigerator at a temperature of 11-12 ℃. Fruits stored under ambient conditions developed external colour faster than those stored at a lower temperature. Brix values for fruits treated with Triadimefon decreased with time. Fruits stored at lower temperatures gave least Brix values as compared with those stored under ambient conditions. Percentage titratable acid （%TA） of fruits stored at low temperatures increased over time. Fruits stored at lower temperatures recorded lower pH compared with fruits stored under ambient conditions. Palmer fruits recorded higher %Brix to %TA ratio, indicating a higher sweetness level. The firmness of Palmer fruits kept at lower temperatures increased with time when compared with Keitt fruit. Fruits treated with hot water at 53 ℃ and/or stored at low temperatures （11-12 ℃） had lower levels of anthracnose infection than other treatments. Keitt fruits were more susceptible to anthracnose infection than Palmer fruits. Mango fruits should therefore be treated with hot water at 53 ℃ and then stored at low temperatures （11-12 ℃） in order to slow down the rate of ripening and to reduce anthracnose infection.

Effect of Storage Temperature on the Quality of Fresh-cut Cattail

Fresh-cut cattail was extremely not resistant to store at room temperature.In the first day,it began to etiolate and rot,the fiber content increased,but the vitamin C content and reducing sugar content decreased.The aerobic bacterial count increased,the weight loss rate sharply increased,and the sensory quality and food value were gradually lost.Low temperature storage could decrease the loss of vitamin C and reducing sugar of fresh-cut cattail,reduce the weight loss rate and delay the increase of fiber content,maintain the water and nutrient of fresh-cut cattail,and the storage effect of 0 ℃ was better than 4 ℃.

Analysis on the Changes in Fruit Quality of ‘Beishan’ Apricots during Storage at Room Temperature

[Objectives]This study was conducted to understand the changes in fruit quality during storage of local high-quality apricot variety ‘Beishan’ in Xinjiang at room temperature, and to clarify the suitable storage time of the variety. [Methods] Under normal temperature storage conditions, the changes of fruit weight, firmness, soluble solids, titratable acid, soluble sugar, vitamin C and rot rate were observed every day. [Results] With the increase of storage days at room temperature, the fruit weight and firmness of ‘Beishan’ apricots gradually decreased;the contents of titratable acid and vitamin C decreased gradually;and the contents of soluble solids and soluble sugar increased slightly on the 2^(nd) day of storage, and then gradually decreased. The fruit quality began to decline sharply after the 6^(th) day of storage. The fruit began to rot on the 3^(rd) day of storage, and the rot rate was higher than 60% and increased significantly after the 6^(th) day. After the ‘Beishan’ apricots were stored at room temperature until the 6^(th) day, the fruit quality began to decline sharply, and the rot rate exceeded 60%. The suitable storage time at room temperature was about 6 d. [Conclusions] This study provides data support for the research and promotion of the ‘Beishan’ variety.

Effects of Cooking Temperature and Storage Time on the Quality of Macadamia Nut Oil

The purpose is to study the influence of cooking and storage habits on the quality of macadamia nut oil,so as to provide reference for macadamia nut processingenterprises and consumers.Macadamia oil was treated at 100℃,200℃,300℃,microwave heating,45℃constant temperature storage,natural light for different times,and its acid value,peroxide value,squalene,sterol and fatty acid content were detected according to the national standard method.The results showed that the acid value and peroxide value increased with time.The acid value and peroxide value of macadamia oil cooked at 300℃and stored under natural light were higher than those heated by microwave and stored at 45℃,and increased rapidly with the increase of cooking and light time.The acid value was as high as 0.77 mg/g,with an increase of 63.8%,and the peroxide value was as high as 6.18 mg/g,with an increase of 43.7%.As for squalene,it decreased in varying degrees with heating time and storage time.Squalene in macadamia oil cooked at 300℃and stored under natural light were lower than those heated by microwave and stored at 45℃constant temperature,respectively,and decreased rapidly with the increase of cooking and light time,with the reduction ranges of 38.6%and28.4%respectively;Stigmasterol was not detected in macadamia oil.But in macadamia oil the content ofβ-sitosterol was 0.132 g/100 g,and the content did not change significantly in each treatmentgroup.In the experimental treatment group,the content of fatty acids in macadamia oil had different trends.After treatment at 300℃for 20 minutes,the content of oleic acid decreased by 75.66%,the content of palmitic acid decreased by 75.28%,and thecontent of palmitic acid decreased by 74.12%.In conclusion,low temperature heating,microwave heating and storage away from light can better preserve the quality of macadamia oil,this study will provide a theoretical basisfor the rational utilization of macadamia oil as cooking oil.

Effects of Nitrogen-controlled Atmosphere Storage on the Quality of Ordinary Late Japonica Rice

Nitrogen-controlled atmosphere has been internationally recognized as a green grain storage technology.This study used Jiangsu ordinary late japonica rice as the test material and investigated the effects of different nitrogen concentrations(88%,93%,and 98%)and different storage temperatures(10,20,and 30℃)on the rice quality indexes during nitrogen-controlled atmosphere storage.The results showed that the water content of rice in different nitrogen-controlled atmosphere groups fluctuated between 12.85%~13.15%at 20℃,which was significantly lower than that in the control group.High-concentration nitrogen-controlled atmosphere treatment(93%and 98%)effectively slowed down the fatty acid value,malondialdehyde(MDA)content,and electrical conductivity of rice,and also significantly inhibited the rapid increase in the final viscosity and water absorption of rice starch,while the changes in the peak viscosity and attenuation value of rice were not significantly different from those of the control group.Meanwhile,the impacts of controlled atmosphere storage with 98%nitrogen concentration on the water content,fatty acid value,MDA content,electrical conductivity,gelatinization characteristics,and water absorption of rice at 10,20,and 30℃were studied.It was found that all quality parameters,except the MDA content,changed most gently at 10℃.In conclusion,the combined treatment of nitrogen-controlled atmosphere storage(98%)and low temperature(10℃)can effectively delay the quality deterioration of ordinary late japonica rice.

Effect of dietary protein sources and storage temperatures on egg internal quality of stored shell eggs

This study was conducted to evaluate the effects of various protein sources(soybean meal, SBM; cottonseed protein, CSP; double-zero rapeseed meal, DRM) on the internal quality(Haugh unit, yolk index,albumen pH,yolk hardness and yolk springiness) of eggs when stored at either 4 or 28℃ for 28 d. A total of 288 laying hens(32 wk of age) were randomly allotted to 6 treatment groups(4 replicates per treatment) and fed diets containing SBM, CSP, or DRM individually or in combination with equal crude protein content(SBM-CSP, SBM-DRM, and CSP-DRM) as the protein ingredient(s). A 6 x 2 factorial arrangement was employed with dietary types and storage temperatures(4 and 28℃) as the main effects. After 12 wk of diet feeding, a total of 216 eggs was collected for egg internal quality determination.The results showed as follows: 1) lower egg quality was observed in the DRM group compared with the other groups when stored at 4 and 28℃ for 28 d(P < 0.05), while there was no difference in egg internal quality among the other groups. 2) The CSP diet resulted in higher yolk hardness compared with the other diets when eggs were stored at 4℃ for 28 d(P < 0.05). Lower Haugh unit was observed in the DRM and SBM-DRM groups compared with the other groups when eggs were stored for 28 d at 4℃(P < 0.05).3) Yolk breakage occurred in the DRM group and eggs could not be analyzed for egg internal quality when stored at 28℃ for 28 d. The overall results indicated that CSP or DRM as the sole dietary protein source for laying hens may adversely affect the internal quality of stored eggs as compared with the SBM diet, and half replacement of CSP combined with SBM may maintain similar egg quality to SBM diet alone for eggs stored under refrigerated conditions.

Changes in Physicochemical,Cooking and Sensory Characteristics of Rice Shifted from Low-temperature Storage

The physicochemical, cooking, and sensory characteristics of stored rice were measured in order to investigate the quality changes in it after low-temperature storage. The quality of the stored rice was compared to that of the rice stored at ambient temperature(20℃, 30%–70% RH) at a 25 d interval during 200 d of storage. The rice was stored in a temperature controller at 4℃ for 3 months and later under a simulated condition similar to that of the main rice consumption areas in China(35℃, 80% RH and 30℃, 70% RH). The results showed that the fatty acid value, b value, and moisture content of rice stored at 35℃, 80% RH and 30℃, 70% RH had increased significantly, whereas its L value had decreased as compared to the rice stored at ambient temperature. Higher temperature storage caused a greater water uptake, whereas the dry mass in the residual cooking water notably reduced under the storage at 35℃ as compared to that at 20℃. Hardness increased and adhesiveness reduced under the storage at 35℃ as compared to that at 20℃. The shelf life of the stored rice which was shifted from a low temperature to three storage conditions used in this study was 75 d, 100 d and 150 d, respectively, in the main rice consumption areas of China.

Effect of precooling temperature on physiological quality of cold stored Agaricus bisporus

Effect of precooling temperatures(2℃,6℃,10℃and 14℃)on the physiological quality of postharvest Agaricus bisporus during cold storage was investigated.After six hours’precooling,Agaricus bisporus was stored at 3℃and sampled on day 3,6 and 9,respectively,for physiological quality analysis.Results showed that physiological quality of the Agaricus bisporus increased with the decrease of precooling temperature in the range of 2-14℃.Precooling at 2℃before cold storage had a positive impact on the storage quality of Agaricus bisporus.The decrease of hardness,whiteness and pH value was delayed,while the increase of cell membrane permeability and PPO and POD activities was restrained.Whiteness value of the Agaricus bisporus precooled at 2℃was above 80 on day 9,which means it was still acceptable,but the Agaricus bisporus precooled at 6℃and 10℃lost their commercial values.

Design and Performance of a Controlled Environment Mini-chamber for Measuring Produce Quality Deterioration

To minimize losses between harvest and retail display, a system is needed to track temperature and RH exposure of fresh produce and predict its quality at each step of the distribution chain. With accurate models, such system could （1） identify problematic situations before losses occur; （2） become a management tool for decision makers; and （3） help quantify the real impact of individual inappropriate conditions. A project was initiated to develop models required for such a decision system. Because the data required to develop models were not available for most fruit and vegetables, a series of storage trials was planned for measuring changes in physiological and microbial quality, and development of physiological disorders and/or diseases, as a function of time, temperature and RH. To meet this objective, controlled environment mini-chambers were designed, built and instrumented for measuring the effect of traceable environmental conditions encountered during storage and transportation of fresh horticultural produce of similar size and shape as tomato. Detailed design and performance evaluation of these mini-chambers are presented.

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。

冰温贮藏期间淀粉添加对水滑肉品质的影响

水滑肉是中国传统的菜肴,具有爽滑细嫩、鲜香无比的特点。为了探究水滑肉淀粉外壳变化对水滑肉品质的影响,以质构、剪切力、水分含量、回生程度、淀粉热力学特性等为评价指标,研究了在冰温贮藏期间水滑肉品质的变化情况。结果表明:与水煮肉进行对照,在冰温贮藏期间淀粉的添加显著抑制了水滑肉的硬度、咀嚼性及剪切力的增加;水滑肉在贮藏期品质指标劣化,但感官得分优于对照组。在冰温贮藏期间,水滑肉外壳的水分含量、糊化焓值及1047 cm^(-1)和1022 cm^(-1)处的峰强度比值(R_(1047/1022))依次增加了7.29%、327.42%、5.17%,增长幅度均低于淀粉组(P<0.05);肉的存在显著减缓了水滑肉淀粉外壳的回生(P<0.05)。在冰温贮藏条件下,淀粉外壳的回生与水滑肉的质构指标呈现显著正相关(P<0.05),即淀粉外壳的回生会劣化水滑肉的硬度、咀嚼性和剪切力。冰温条件下,肉中水分向淀粉外壳转移可能会延缓淀粉外壳的回生,从而延缓其品质劣化。研究结果可为水滑肉预制菜肴品质研究提供参考。

精准控温对甜樱桃贮藏品质的影响

为解决低温贮藏中库温波动造成樱桃果实品质劣变加剧的问题,探究精准控温对甜樱桃贮藏品质的影响,比较了0℃和4℃精准控温,以及(0±0.60)℃和(0±2.23)℃两种温度波动条件对‘美早’甜樱桃采后贮藏品质的影响。结果表明:相同贮藏温度下,温度波动越大,保鲜效果越差,(0±2.23)℃显著加剧了樱桃贮藏期间品质劣化,保鲜效果比4℃精准控温更差,说明在一定条件下,与不适宜的贮藏温度相比,温度波动对果实品质的影响更为显著。0℃精准控温保鲜效果相比4℃精准控温更好,有效地抑制了甜樱桃果胶甲酯酶(PME)和多聚半乳糖醛酸酶(PG)活性的增加及丙二醛(MDA)含量的上升,减少果实软化、腐烂和凹陷现象,降低可溶性固形物(TSS)和可滴定酸(TA)的损失,抑制多酚氧化酶(PPO)活性的上升,提高苯丙氨酸酶(PAL)活性,促进了酚类物质的积累,保持花青素含量的稳定,延缓了贮藏期间的颜色变化。综上,甜樱桃的适宜贮藏温度为0℃,并且温度波动越小,保鲜效果越好。本研究结果可为甜樱桃精准控温贮藏提供理论和技术依据。

不同贮藏温度下柠檬味矿泉气泡水品质变化及货架期预测研究

探讨以五大连池矿泉水为原料制作的柠檬味矿泉气泡水在不同贮藏温度下的品质变化,基于加速货架期实验(ASLT)预测其货架期。对样品在25℃、35℃和45℃下的贮藏特性进行分析,测定气泡水的pH值、瓶内压力、感官品质等指标。结果显示,温度对果味矿泉气泡水的品质有显著影响,特别是瓶内压力和感官品质变化显著。利用ASLT方法预测得出果味矿泉气泡水在25℃下的货架期为130~135 d。

低温结合不同厚度保鲜膜对‘巨峰’葡萄贮藏品质的影响

为探究不同厚度低密度聚乙烯保鲜膜对采后葡萄质构品质及贮藏特性的影响,以‘巨峰’葡萄为试材,分别用0(无包装组,CK)、0.02、0.03、0.04、0.05 mm和0.06 mm厚度的LDPE保鲜膜袋包装,于(1±1)℃低温下贮放42 d,每隔7 d测定其贮藏期质构品质及贮藏特性指标,进行相关性分析,并采用主成分分析法确定最佳保鲜膜厚度。结果表明:与CK组相比,不同厚度LDPE保鲜膜均能延缓葡萄掉粒率及失重率的上升,较好地保持葡萄色泽和亮度,同时能抑制水分、可溶性糖和可溶性蛋白含量的下降,延缓果皮和果肉硬度的降低。CK组、0.05 mm和0.06 mm LDPE组分别在贮藏28 d、35 d和35 d时失去商品价值,而0.02 mm、0.03 mm和0.04 mm LDPE组能将葡萄保鲜期延长至42 d。相关性分析显示,葡萄贮藏期间质构、感官和营养各指标之间密切相关。PCA结果显示,0.03 mm LDPE组置信圈较窄小,保鲜效果最好。综上,0.03 mm LDPE能较好地保持‘巨峰’葡萄的贮藏品质。

不同杀菌方式和储藏条件对植物蛋白肉品质的影响

植物蛋白肉含有大量的水分和蛋白质,同时含有少量油脂,在常温下储藏容易变质。为探究不同的储藏条件对植物蛋白肉品质的影响,分别对不同杀菌方式、不同储藏温度的植物蛋白肉进行硬度、咀嚼度、组织化度、色泽以及卫生指标的测定。结果表明:121℃杀菌20 min、100℃杀菌20 min两种方式均会对产品的品质产生显著影响(P<0.05),但100℃杀菌20 min引起产品品质变化的程度更小;在未杀菌、冷冻储藏,100℃杀菌20 min、冷藏以及121℃杀菌20 min、冷藏3种长期储藏方式下,随着储藏时间的延长,产品的硬度、咀嚼度整体上都呈逐渐变大的趋势,产品的L^(*)逐渐降低,而a^(*)、b^(*)逐渐升高;产品的组织化度整体上在未杀菌、冷冻储藏过程中无显著性变化(P>0.05),在100℃杀菌20 min、冷藏和121℃杀菌20 min、冷藏条件下显著下降(P<0.05)。选用100℃杀菌20 min的方式并冷藏保存效果最好,研究结果为植物蛋白肉的杀菌和储藏提供了可靠依据。

不同贮青温度及方式对红碎茶品质的影响

本实验以控温15、25℃,常温(22~28℃)以及沤红4种处理的英红九号茶青制成的红碎茶为实验材料,采用感官审评、顶空固相微萃取与气相色谱-质谱联用技术和生化分析技术研究不同贮青处理对红碎茶感官品质、香气物质、生化成分的影响。结果表明:4个处理中,15℃贮青能提高红碎茶的鲜爽度、甜度及甜香挥发性物质的含量,更有利于品质形成,而茶青沤红劣变会显著影响红碎茶感官品质和表征品质的化合物含量,实验结果可为茶青管理及红碎茶品质的提升提供参考。

不同环境温度下冰藏黄颡鱼品质及微生物菌群变化研究

为研究宰杀后的黄颡鱼(Pelteobagrus fulvidraco)在不同环境温度下冰藏过程的品质变化和保鲜时间,测定了不同环境温度冰藏黄颡鱼肌肉的质构指标、pH、硫代巴比妥酸(TBA)、高铁肌红蛋白(MetMb)、挥发性盐基氮(TVB-N)、营养成分(水分、粗蛋白、粗脂肪、粗灰分)的含量,并通过16S rRNA高通量测序分析了黄颡鱼肌肉微生物菌群的变化。结果显示:15、27、33℃温度下冰藏黄颡鱼肌肉各质构指标均随时间延长而下降。各温度组TBA、TVB-N和MetMb含量随时间延长呈上升趋势,三组的TVB-N和MetMb含量在12 h冰藏期间均没有超过国家标准限值,15℃组TVB-N含量始终处于一级鲜度标准。各温度组肌肉营养成分中粗脂肪、粗灰分和水分含量随冰藏时间延长而有所下降。微生物组分析表明在冰藏期间,三个温度组的黄颡鱼肌肉均未产生有害病原菌微生物。研究表明,宰杀后的黄颡鱼33℃时冰藏保鲜时长为4 h,27℃时冰藏保鲜时长为6 h,15℃时冰藏保鲜时长可达12 h。

近冰温贮藏对西梅的采后品质及活性氧代谢的影响

该试验以新疆‘法兰西’西梅为试材,采用不同贮藏温度(近冰温、1~2℃和4~6℃)处理,定期测定西梅果实品质及活性氧代谢相关指标。结果表明,西梅果实冰点为-2.8℃,确定西梅果实近冰温的贮藏温度为-1~-1.5℃,与1~2℃和4~6℃贮藏相比,近冰温贮藏可以显著维持西梅果实的表面色泽、硬度、可溶性固形物、可滴定酸和抗坏血酸的含量,有效降低西梅果实的呼吸强度。同时近冰温贮藏有效提高了西梅果实的过氧化物酶、过氧化氢酶和超氧化物歧化酶的活性,显著减缓超氧阴离子的产生速率,抑制H_(2)O_(2)的生成,进一步影响丙二醛的积累与细胞膜透性的上升。综上,近冰温贮藏可有效调控采后西梅果实活性氧代谢的平衡,保持其采后贮藏品质,从而延长其采后贮藏时间。该试验旨在为西梅采后贮藏保鲜提供技术参考和理论依据。

新疆椒麻鸡腿的品质变化及货架期预测

为了探究新疆椒麻鸡腿贮藏期间品质变化并对其货架期进行预测。本文以新疆椒麻鸡腿为研究对象,以酸碱度值(Potential of hydrogen,pH)、色泽、硫代巴比妥酸值(Thiobarbituric acid reactive substances,TBARS)、挥发性盐基氮(Total volatile basic nitrogen,TVB-N)、菌落总数、大肠菌群及感官品质为评价指标,利用加速性破坏实验,研究不同贮藏温度(35℃和45℃)下椒麻鸡腿的品质变化,以感官得分70分或菌落总数接近国家标准作为货架期终点,并预测出常温(25℃)下椒麻鸡腿的货架期。结果表明:不同贮藏温度下的椒麻鸡腿随着贮藏时间的不断延长,pH呈先下降后上升趋势,L^(*)值整体呈下降趋势,而a^(*)值、b^(*)值、TBARS值、TVB-N含量和菌落总数均呈上升趋势,感官评分则不断下降,在贮藏期且45℃的变化速率高于35℃,在35℃贮藏温度下,理论货架期为24 d,在45℃贮藏温度下,理论货架期为9 d,在货架期终点样品品质出现不可接受的损失。根据Q_(10)模型计算出Q_(10)=2.6,根据模型预测出常温(25℃)条件下理论货架期为62 d。

低温驯化结合冰温贮藏对猕猴桃品质的影响

目的研究不同低温驯化处理方式结合冰温贮藏对猕猴桃品质的影响,为猕猴桃贮藏保鲜提供新技术。方法将猕猴桃在冰温(-0.5±0.2)℃、快速驯化(4℃驯化48 h)结合冰温和慢速驯化(10℃驯化24 h后再4℃驯化24 h)结合冰温的条件下贮藏180 d,定期测定猕猴桃相关指标。结果贮藏结束时,对照组可滴定酸(Titratable Acid,TA)含量为0.733%、维生素C(Vitamin C,VC)含量为208.7 mg/kg、硬度为0.692 N,而慢速驯化组的TA含量为1.053%、VC含量为259.4 mg/kg、硬度为1.119 N。与对照组相比,低温驯化结合冰温贮藏能够降低质量损失率、冷害率及腐烂率,抑制可溶性固形物(Soluble Solids,TSS)、丙二醛(Malondialdehyde,MDA)含量的增加,脂氧合酶(Lipoxygenase,LOX)活性的上升和自由水的损失,以及保持了过氧化物酶(Peroxidase,POD)的活性。结论慢速驯化比快速驯化处理能够更有效地保持冰温贮藏猕猴桃的品质,延长采后贮藏保鲜的时间。