To investigate the effects of three circulation methods including normal temperature,cold chain,and broken cold chain on the flavor substances of fresh Lentinula edodes before and after storage and transportation,the changing trends of volatile flavor compounds and taste components of L.edodes during simulated transportation under the three temperature conditions were analyzed using an electronic nose,gas chromatography-ion mobility spectrometry(GC-IMS),an electronic tongue,high performance liquid chromatography(HPLC),and an automatic amino acid analyzer.The results showed that electronic nose was able to quickly distinguish between the aroma characteristics of L.edodes under different simulated temperature conditions.In total,55 volatile compounds were detected by GC-IMS,including 16 alcohols,10 aldehydes,8 terpenes,6 ketones,4 esters,and 11 other compounds.The electronic tongue revealed differences in the sourness,bitterness,astringency,umami,richness,and saltiness among early storage and transportation(control),simulated normal temperature logistics(NTL),simulated cold chain logistics(CCL),and simulated broken chain logistics(BCL),with the CCL group being characterized by moderate sourness and prominent umami.In the NTL,CCL,and BCL groups,the total amounts of free umami amino acids were 90.82,81.83,and 84.31 mg/g,respectively,and the 5'-nucleotide contents were 122.99,107.42,and 118.27 μg/g,respectively.Among them,the volatile flavor compounds and taste components in the CCL group were most similar to those in the control group,indicating that consistent low-temperature conditions are helpful for preserving the flavor quality of L.edodes during storage and transportation.In contrast,the BCL group,which experienced temperature fluctuations during both storage and transportation,exhibited slightly lower flavor quality than did the CCL group due to the negative impact on the flavor compounds before entering the shelf life.In conclusion,in the post-harvest circulation process of L.edodes,cold-chain transportation is needed to minimize quality deterioration caused by temperature fluctuations during storage and transportation.The results provide valuable insights for improving the cold chain distribution system for L.edodes.

In order to investigate the effects of different doses of 60Co-y-ray irradiation on rice,this experiment employed a texture analyzer,a rapid viscosity analyzer,a differential scanning calorimeter,a rheometer,an X-ray diffractometer,and a Fourier transform infrared spectrometer to characterize the eating quality of rice and the physicochemical properties and structure of rice starch.The results indicated that as irradiation dose increased,the water absorption and volumetric expansion of rice during cooking,and the pH,dissolved solid content and iodine blue value of rice broth fell significantly(P＜0.05).High doses of irradiation resulted in a noticeable increase in the total color difference(△E)of rice compared with that before irradiation,and a △E of 12.53 was obtained at 10 kGy,indicating a significant color change.Also,the irradiation notably affected the hardness of cooked rice.The peak viscosity,setback value,and gelatinization enthalpy of rice starch decreased significantly(P＜0.05)with the increase in irradiation dose;the irradiation also reduced the rigidity,elasticity,relative crystallinity and orderliness of rice starch,with the crystallinity being decreased from 23.68％to 15.69％.The measurement results of cooking indicators,rice soup properties,△E,and texture characteristics indicate that higher irradiation doses reduced the edible quality of rice.Moreover,the contents of slowly digestible starch and resistant starch in irradiated rice starch increased,with the latter being increased to 20.22％after irradiation treatment at 4 kGy.Compared with the unirradiated control,the irradiation reduced the hydrolysis rate of starch.Overall,y-ray irradiation altered the crystalline structure of starch,thereby enhancing its pasting and rheological properties and inhibiting its digestibility,but rice is not suitable for high doses of irradiation treatment.This study provides theoretical guidance for the production of irradiated rice and its products,as well as for the modification of starch.

以双孢蘑菇粉为主要添加料制备冻干型食用菌特色溶豆,分析了不同粒度(20目、60目、100目、超微粉)的双孢蘑菇粉对溶豆的食用品质的影响.结果表明,添加双孢蘑菇粉后,溶豆的色泽明显变暗变深,挥发性风味成分含量显著升高,水合能力和质构特性变化明显;随着添加双孢蘑菇粉粒度的降低,溶豆色泽显著变亮变白,挥发性风味成分含量逐渐增大;溶豆的水合能力及感官评分均呈先升高后降低的趋势,而复水时间及韧性、硬度和粗糙度等指标则呈现先减小后增大的趋势.研究发现,添加双孢蘑菇粉超微粉可显著改善溶豆的色泽,但对最终产品的口感产生了一定的负面影响;当双孢蘑菇粉粒度为100目时,溶豆的食用品质最佳,其水合能力为2.82 g/g,复水时间为51.38 s,韧性(距离)为0.20 mm,最大穿刺硬度为1083.00 g,粗糙度为26.40.100目的双孢蘑菇粉适宜用于制备食用菌特色溶豆,可较好地保证产品的食用品质.该研究可为双孢蘑菇特色食品的开发及综合利用提供一定的理论参考.

为了降低冷冻干燥过程中能耗、推动冻干技术在食品中的应用,该研究应用在线调控预冻-冷冻干燥一体化设备进行食用菌汤块制备中试研究.对实际生产中冻结阶段(预冻温度、装盘物料厚度)、升华阶段(干燥仓压强、加热板温度)、解析阶段(水分转换点、升温工艺)等工艺进行了试验分析及优化,得出了适宜食用菌汤块冻干的节能工艺条件.提出了解析阶段的分步阶段升温法,并对解析阶段冻干曲线进行了拟合分析.结果表明,预冻温度设定为-35℃,装盘物料厚度为15 mm,干燥仓压强为25 Pa,汤块含水率为83.1％;升华阶段加热板温度为-10℃,解析阶段起始点为1148 min,汤块含水率为9.2％,解析阶段采用分步阶段升温工艺(-10℃→2.5℃(70 min)→15℃(70 min)→27.5℃(70 min)→40℃(144 min))为较优选择,在此条件下,制备的汤块成品率为99.2％,感官品质指标综合分值为8.37,能耗为1.75 kW·h/kg,汤块含水率为4.3％.Boltzmann模型能较好表征解析阶段的冻干过程.该研究为冻干过程参数优化和能耗分析提供参考,为冻干技术应用于方便食品开发提供了技术依据.