摘要
【目的】中国是稻谷产销大国,稻谷安全储运至关重要。通过实验室模拟动态温湿度条件,研究动态储运条件下稻谷的品质变化和水分迁移规律,为优化稻谷安全储运条件提供参考。【方法】本研究通过动态温湿度的实验模拟,采用14%、16%、18%、20%、22%等5种不同水分稻谷进行3个月低温(10℃左右波动)、中温(20℃左右波动)和高温(30℃左右波动)的动态储运,观测微生物生长、质构品质、脂肪酸值和低场核磁共振数据的变化,阐明温度和水分对稻谷储运特性的影响。【结果】细菌总数随着储运时间延长而增加,不同温度和不同水分含量稻谷细菌总数的增加趋势不同;细菌总数随着温度的增加而增加。霉菌数量随着储运时间延长呈升高趋势,在中、高温下,稻谷霉菌数量显著增加,而且温度越高,霉菌数量上升趋势越明显;初始水分14%和16%的稻谷在低温、中温、高温3个动态模拟条件下,霉菌发生都处于较低水平;初始水分含量18%以上稻谷在中温和高温动态模拟储运15 d时霉菌发生显著高于水分含量为14%和16%的稻谷。稻谷蒸煮硬度和弹性随着储运时间延长逐渐上升,初始水分含量越大硬度上升越快(P<0.01),储运过程中硬度与稻谷中的初始水分含量显著负相关,初始水分含量越高,硬度值越小,稻谷质地越好;初始水分含量对稻谷弹性影响显著(P<0.01);黏着性则随着储运时间的延长呈下降趋势,温度和水分对黏着性均有显著影响(P<0.05)。脂肪酸值与初始水分含量呈正相关(P<0.01),稻谷初始水分含量越高,脂肪酸值增加越明显;温度对高水分稻谷脂肪酸值影响尤为明显,温度越高,脂肪酸值上升越快。低场核磁信号总量(T_(2w))随储运时间的增加而减小,T_(2w)信号总量与水分含量呈极显著的线性正相关(P<0.01)。核磁共振图像显示,稻谷储运15 d时,水分主要集中在表皮层和糊粉层;储运30 d后,表层水分损失,水分分布更为均匀。【结论】水分含量14%或16%的稻谷短期(15或30 d)储运可以提高稻谷主要质构品质;温湿度动态变化(中温和低温)的长时间储运过程中稻谷初始水分应限定在16%及以下。
【Objective】 Safe storage and transportation of rice is very important because China is the major rice producer and consumer in the world. Through laboratory simulation of dynamic temperature and humidity conditions, the rice quality and moisture migration law of the dynamic storage and transportation conditions are studied. The objective of this paper is to provide reference for the construction of dynamic storage and transportation of rice. 【Method】 Through dynamic temperature and humidity simulation experiment, five moisture content paddy rice（14%, 16%, 18%, 20%, and 22%） were stored and transported for three months respectively at low temperature（fluctuates around 10℃）, middle temperature（fluctuates around 20℃） and hightemperature（fluctuates around 30℃）. During the storage and transportation, the changes of microbial growth, texture quality, fatty acid value and low field nuclear magnetic resonance（NMR） data were measured to clarify the influence of temperature and moisture content on paddy rice during storage and transportation. 【Result】 Aerobic plate count increased with prolonged time, the increasing trends of aerobic plate count in different temperatures and moisture content for paddy rice were different. Aerobic plate count increased with rising temperature. The mould number raised with prolonged storage and transportation time and the mould number increased significantly under middle and high temperature. The higher temperature was, the more obviously mould number increased; mould happened at lower levels when 14% and 16% moisture content paddy rice storage and transported at low, middle and high temperature. The mildew occurrence of 18% and higher moisture content paddy rice was significantly higher than 16% and 14% moisture content paddy rice during 15 days storage and transportation at middle and high temperatures. The hardness and springiness of cooking rice increased gradually with prolonged time. The higher initial moisture content was, the faster the hardness rose（P0.01）. The hardness had a significant negative correlation with the initial moisture content of paddy rice; the influence of initial moisture content on springiness was significant（P0.01）. The adhesiveness of paddy rice reduced with prolonged time, the influence of temperature and moisture content on adhesiveness was significant（P0.05）. The fatty acid value and the initial moisture content were positively correlated（P0.01）, the higher initial moisture content was, the more obviously fatty acid value of paddy rice increases. The influence of temperature on fatty acid value was particularly apparent, the higher temperature was, the faster fatty acid value rises. The low field nuclear magnetic total semaphore t（T_（2w）） decreased with the increase of storage and transportation time, T_（2w） total semaphore and moisture content exhibited significant linear positive correlation（P0.01）. As magnetic resonance imaging（MRI） exhibits, moisture mainly concentrates on epidermis and aleurone layer when paddy rice was stored and transported 15 days. After 30 days storage and transportation, surface moisture losses and the moisture distribution became more uniform. 【Conclusion】 The short storage time（15 or 30 days） and transportation of relative high moisture（14% or 16%） paddy rice can improve rice main the texture＇s quality. The initial moisture content of paddy rice should be controlled under 16% during a long time transportation with dynamic variation of the temperature and humidity（around low and middle temperature）.
出处
《中国农业科学》
CAS
CSCD
北大核心
2016年第1期163-175,共13页
Scientia Agricultura Sinica
基金
国家粮食公益性行业科研专项(201313010)
江苏高校自然科学研究项目(13KJB550010)
江苏高校优势学科建设工程资助项目(PAPD)
关键词
稻谷
储运
动态模拟
温湿度变化
品质特性
paddy rice
storage and transportation
dynamic simulation
temperature and humidity change
quality characters
