Grain storage systems and effects of moisture,temperature and time on grain quality - A review

Global grain production has been increasing every year, which highlights the need for investment, maintenance, and effective management in warehouses. Warehousing is a major bottleneck as it influences the possibility of negotiating for better market prices. In order for profitability to be increased, assurance of product quality for the consumer is necessary. Hence, there is a need for standardization of scientific research and the production chain in this field. The purpose of this bibliographic review is to describe the existing storage systems for grains, steps to be taken for care, and the main studies carried out in this field, to guarantee grains of good quality. The maintenance of the characteristics of the grains after harvest, is essential to guarantee grains of good quality to consumers. However, there are still deficiencies in the field of grain storage, and features of the different systems and conditions to be adopted for each of them are provided in this review.     

两种储粮水分粳稻储藏周期内品质变化及效益分析

水分是影响粮食品质的重要因素,应用空调控温储粮技术,以辽宁盘锦地区粳稻为研究对象,选取正常水分(14.4%)和偏高水分(15.5%)粳稻,定期扦取样品检测各项品质指标变化。结果表明,随着储藏时间的延长,两种水分粳稻的储藏品质变化相近,但偏高水分粳稻的加工品质及食用品质优于正常水分粳稻,能够较好的保持粳稻的营养成分,提高粮食仓储、加工企业的经济效益。     

水分测定仪在粮食检验中的使用

在粮食检验中,对水分测定仪的使用,应当在仪器的放置环境、样品的制备、温差的调整、样品的自然降落、仪器的校订等方面细心操作,以取得准确数据。     

浅谈粮食仓储质量的管理与实践

根据多年来的仓储管理实践,提出了创新质量管理机制,强化质量管理措施,加强人员队伍建设,加大清理设备和科技储粮投入等保障措施,确保收购、储存、销售的粮食质量良好、卫生安全.     

水分对优质稻储藏品质的影响

为改善优质稻储藏入库前含水量,本研究以不同水分梯度(11.5%、12.5%、13.5%、14.5%、15.5%、16.5%)的优质稻为研究对象,通过放入15、20℃进行模拟储藏。研究储藏过程中其整精米率、发芽率、发芽势、脂肪酸值、峰值黏度的变化情况。结果表明:准低温下储藏,含水量为12.5%～14.5%范围内整精米率较好,含水量为14.5%以下,其发芽率、发芽势较好,含水量为12.5%～15.5%都能保证脂肪酸值在较好水平,含水量对稻谷糊化特性影响较显著,含水量较低时峰值黏度较低,含水量升高峰值黏度逐渐升高;准低温以下温度储藏对优质稻整精米率、发芽率、发芽势影响不大,温度越高脂肪酸值、降落数值增加越快,RVA糊化特性受温度影响较大,温度高峰值黏度变化快。     

Comparative effects of hermetic and traditional storage devices on maize grain: Mycotoxin development,insect infestation and grain quality

A large-scale study was conducted to assess which of the five most accessible hermetic storage devices on the Kenyan market fulfill the needs of smallholder farmers by positively impacting three major areas of concern: insect infestation, grain quality, and mycotoxin (aflatoxin and fumonisin) contamination. Efficacy of two hermetic silos (plastic and metal) and three hermetic bags (PICS, GrainPro's GrainSafe™, and Super Grain) was directly compared to current maize storage in polypropylene (PP) bags under local environmental conditions using representative storage volumes during a 6-month storage period. Impact of maize grain stored at typical (∼15%) and recommended (<13.5%) moisture levels and potential efficacy losses through frequent interruption of the underlying hermetic principals was assessed. Hermetic storage significantly reduced the increase in aflatoxin compared to PP bags regardless of the moisture level of the grain. An <5% per month aflatoxin increase was achieved by three of the five devices tested: Metal silo, PICS and GrainSafe™ bag. A strong correlation between grain moisture, storage time and aflatoxin development was found in PP bags, but not in any of the hermetic devices. The same result was not obtained for fumonisin development in stored maize. The rate of Fumonisin increase was similar in all tested devices, including the polypropylene bags, and conditions. The periodic opening of the hermetic devices had no significant effect on the efficacy of the hermetic devices but the repeated disturbance of the PP bags led to a significant increase in aflatoxin levels. The maize weevil Sitophilus spp. was most commonly found with a total incidence of 72%. Grain storage under hermetic conditions reduced insect infestation, grain weight loss and discoloration. However, maize storage above recommended moisture levels led to a distinct odor development in all hermetic devices but not the PP bags. Hence, proper grain drying is a prerequisite for maize storage in airtight conditions.     

不同扦样方案对储粮品质检验指标的影响

目的 研究不同扦样方案对粮食品质检验工作的影响,制定适合于当前我国储粮形式的扦样方案。方法 本研究以吉林、河南、辽宁、安徽等省份的小麦和玉米储备仓为实验仓,采用不同的粮食扦样器、扦样方案进行扦样,随后对所扦样品进行质量指标、储藏品质指标以及卫生指标的测定,其中仓型涉及浅圆仓、房式仓以及立筒仓。结果 研究结果显示所使用电动吸入式扦样器杂质含量略高于套管式扦样器,但数据差异性并不显著(P>0.05)。所制定扦样方案中的分区设置检验单位、不同扦样顺序、点样比例对粮食品质指标的检验也没有显著性差异(P>0.05)。结论 通过对不同省份、不同储备粮种、多种仓型的实仓扦样实验,结果表明所采用的现代化扦样工具、优化的扦样方案并不会影响扦样样品的检验结果,所获得的扦样数据有望为未来制定更加适合我国粮仓的扦样方案提供支撑。     

Effect of microbial inoculant on quality of alfalfa hay baled at high moisture and lamb performance.

The effectiveness of a microbial hay inoculant in high moisture alfalfa hay was evaluated. Alfalfa (third cutting) was baled at 72% DM without or with inoculant and at 82% DM without inoculant during yr 1. In yr 2, alfalfa (second cutting) was baled at 75% DM without or with inoculant and at 82% DM without inoculant. Application rate of inoculant was 3.8 L/.98 tonne each year. At this application rate, 90 billion cfu were applied per .98 tonne of forage. Hays were core sampled at 0, 14, 30, and 60 d after baling to determine chemical composition. By d 30, all hays had DM content of 89%. In yr 2, 12 wether lambs were assigned to three treatments in a replicated 3 x 3 Latin square. Treatments were chopped, low moisture hay plus corn; chopped, inoculated high moisture hay plus corn; and chopped, high moisture hay plus corn. All diets contained 63% alfalfa hay, 35% ground corn, and 2% minerals and vitamins. In yr 1, inoculated and low moisture hays were not different in chemical composition but were higher in CP and lower in NDF than high moisture hay. Neither NDF nor CP were different among the three hays in yr 2. Average daily gain was not different on the three diets. The feed to gain ratio was lowest for the inoculated hay, intermediate for the low moisture hay, and highest for the high moisture hay diet. Daily gain and feed to gain ratio were not different for lambs fed the inoculated hay baled at 75% DM compared with lambs fed untreated hay baled at 82% DM.     

水分含量对新鲜干酪贮藏特性的影响

对水分含量不同的4组干酪进行贮藏期水分含量、水分活度、pH、酸价、TBA值测定和感官评定。结果表明:干酪水分含量与水分活度随贮藏期呈递减趋势,并且呈正相关关系;酸价随着贮藏期的延长先增加后减少;pH则相反,呈先下降后上升的趋势;TBA值呈逐渐上升趋势。表明水分含量低的干酪,其耐贮藏性较好。感官特征测定在贮藏的第18d开始,干酪逐渐开始出现腐败特征,水分含量较低的干酪感官评分高。     

两种储藏方式对三种原粮储藏品质的影响

研究了充氮气调储藏和常规储藏方式下,在不同温度条件下储藏的小麦、玉米和稻谷的储藏品质随储藏时间的变化规律.结果表明:在低温条件下,两种储藏方式下的粮食品质变化相近,但在高温下充氮气调储藏能较好地保持小麦、玉米和稻谷的储藏品质,比常规储藏的各项指标变化都要缓慢些.由于低温储粮费用较低,在生产中应首推低温储粮.当无法满足低温条件时,粮企可以推广采用充氮气调储藏技术.     

基于Fortran程序对储粮通风温度水分和害虫演替的模拟研究

世界各国因储粮害虫对粮食造成的损失非常严重,为了降低粮食在储藏期间的损耗,所以研究储粮通风过程中害虫增长量的变化至为重要。文章基于多孔介质热湿耦合理论,建立了浅圆仓的粮堆内部热湿传递和流动的数学模型以及害虫和熏蒸经验模型,并基于Fortran语言编程,模拟分析了通风状态下粮堆温度、水分含量、储粮害虫增长量以及杀虫剂浓度衰减的变化。结果表明：通风对粮堆内部温度和水分以及害虫生长影响明显。粮堆的水分含量近似对称分布,而受太阳辐射的影响,粮仓不同方向壁面的温度分布并不对称。储粮害虫在粮仓内的数量分布与温度、水分等因素有关,在壁面附近害虫分布较多,且在筒仓中心区域出现分层现象。杀虫剂浓度衰减也受温度的影响,温度高会影响杀虫剂的降解,导致杀虫剂浓度较低     

Loss of phosphine from unsealed bins of wheat at six combinations of grain temperature and grain moisture content

Hard red winter wheat (1.4 t) at 11.1 or 13.5% moisture content (wet basis) and 20, 25, or 30 degrees C was fumigated with tablets of an aluminum phosphide formulation in unsealed, cylindrical grain bins of corrugated metal. The fumigant leakage rate was manipulated to approximate that commonly encountered in farm and commercial-scale bins of this type. Phosphine concentration profiles were recorded and phosphine loss and sorption were characterized to determine which conditions provided the greatest probability of successful fumigation in these bins. Phosphine leakage and sorption were both positively related to grain temperature and moisture content. The fumigant concentration profiles were compared with previously-published data relating temperature to the developmental rate and fumigant susceptibility of lesser grain borer eggs, which are phosphine-resistant but become less resistant as they age. The mean phosphine concentration observed at the time corresponding to one-half of the calculated egg development time was compared to the lethal concentration (LC(99)) for a 2-day exposure at each temperature-moisture combination. In the low-moisture grain at 20 degrees C, the observed fumigant concentration was below the lethal concentration, due to the long development time under these conditions. At 25 and 30 degrees C in the low-moisture wheat, the likelihood of complete kill appeared more favorable because the fumigant concentration remained above the published LC(99) for more than half of the egg development time. In the wheat with 13.5% moisture content, rapid fumigant sorption and loss resulted in phosphine concentrations below the LC(99) at one-half of the development time at 20 or 25 degrees C. At 30 degrees C, due to the very rapid development rate, the observed phosphine concentration exceeded the LC(99) half-way through the egg development period despite the rapid rate of fumigant sorption and loss. Repeated fumigation of the same grain reduced the rate at which phosphine sorbed into the grain.     

储藏条件对成品粮大米蒸煮品质的影响

试验通过研究成品粮大米在不同的温度(15、20、25℃)及相对湿度(RH:60%、70%)条件下随着储藏时间(30、60、90 d)的延长,其直链淀粉、蒸煮特性、蒸煮质构的变化情况,推动建立成品粮大米储藏新标准。试验结果表明在储藏过程中大米的直链淀粉含量、米汤干物质、凝聚性、胶黏性、咀嚼性随着储藏时间延长显著增大。大米吸水率,膨胀率显著降低。     

Intermediate moisture meat product: biological evaluation of charqui meat protein quality

Charqui is a typical salted and dry Brazilian meat product. A harsh condition for salting and drying during charqui processing could eventually damage its biological value. Therefore protein quality of raw and cooked charqui meat flours was chemically and biologically evaluated by rat growth and nitrogen balance studies. Proximate chemical compositions of desalted raw and cooked charqui flour samples showed protein content of 74.2 and 81.1%, respectively and lipid contents of 20.06 and 13.52%, respectively. There was a good balance of essential amino acids in both samples. Feeding of flour diets prepared from exhaustively desalted and dried cooked and raw charqui samples resulted in high protein efficiency ratios, in high net protein utilisations and high nitrogen balances thus showing a high biological value and also high true digestibility, with NPU similar to casein.     

酶解机械预处理啤酒糟制备饲用蛋白肽

啤酒糟经过粉碎后筛分,筛下物经球磨后粗蛋白含量提高到38.8%,比原样提高了36.1%,水溶性蛋白含量提高到2.53%,比原样提高了3.1倍,经中性蛋白酶液态酶解,水溶性蛋白含量达到12.85%,比原样的7.88%提高了1.6倍,机械预处理显著提高了酶解效率。通过单因素实验和混合水平均匀设计实验,确定了啤酒糟最优酶解条件:加酶量2 400 U/g,酶解温度45℃,酶解pH 8.0,酶解时间8 h,此时水溶性蛋白含量能够达到21.31%,提取率达到54.9%。对酶解液进行真空冷冻干燥,制备饲用蛋白肽,粗蛋白含量达到78.8%,氨基酸含量达到74.6%,必需氨基酸含量达到28.18%,多肽含量达到60.8%。     

再生季稻米蛋白质含量与外观、碾米品质及营养品质的关系

以10个不同品种再生季稻米为研究材料,探究再生季稻精米中蛋白质含量与矿物质元素、氨基酸含量、外观品质、加工品质的关系。结果表明：供试品种再生季稻米畾优1068的加工品质较差,外观品质较好,其精米中蛋白质、矿物质元素以及氨基酸酸含量最高。相关性分析表明蛋白质含量与Cu元素、甘氨酸、丙氨酸、脯氨酸、组氨酸、丝氨酸以及谷氨酸显著正相关（其中与丝氨酸、谷氨酸的相关系数分别达0.97和0.98）;与出糙率、精米率、垩白粒率、垩白度显著负相关。因此,Cu元素及丝氨酸、谷氨酸等含量的增加有利于蛋白质的积累;同时,蛋白质含量的增加会减少再生季稻米中的垩白,改善稻米的外观品质,但是会降低出糙率和精米率     

Investigation on moisture migration,microstructure and quality changes of fresh-cut apple during storage

Moisture migration of fresh-cut apple during 4 °C storage was monitored by low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI). Three water components were identified in apple tissue by LF-NMR T₂ relaxation, corresponding to water in cell wall, cytoplasm and vacuole. The relaxation results also revealed that the moisture migrated from the vacuole to cytoplasm and the mobility of water in vacuole decreased with the extension of storage time. T₂ weighted images of MRI indicated that high density of water appeared at the edge of the fresh-cut apple in the later stage of storage. Breakdown of cell walls and intracellular network were observed by cryo scanning electron microscope (cryo-SEM). Moreover, storage process also led to the decrease in moisture content, browning and softening of fresh-cut apple. In addition, good prediction models have been developed for quality indicators using partial least squares regression based on Carr–Purcell–Meiboom–Gill decay data.