Safe storage guidelines for durum wheat

Storage conditions determine the safe storage period for any grain. Safe storage guidelines for durum wheat have not been developed, despite the fact that it is more susceptible to spoilage than other wheat classes. The rates of deterioration of durum wheat samples with 15, 16, 17, 18, 19 and 20% initial moisture content (wet basis) stored at 10, 20, 30 and 40 °C for 12 wk were studied. The grain deterioration parameters including seed germination, moisture content, appearance of visible mould, invisible microflora, free fatty acid value (FAV), and ochratoxin production were monitored at regular intervals. From these results, safe storage guidelines for durum wheat were developed with respect to the moisture content and storage temperature. Germination rates of the samples decreased with an increase in moisture content, temperature and storage period. Visible mould was found in all high moisture samples (17, 18, 19 and 20%) stored at high temperatures. FAV of the samples increased with moisture content and storage time.     

高温储藏条件下不同水分含量小麦品质变化研究

以开麦21为原料,对其进行鼓风干燥和调质处理,使其水分含量分别为12.5%,9.5%,7.7%和5.9%,在35℃下密封储藏,研究其储藏过程中生活力、电导率、过氧化氢酶活动度、湿面筋含量、干面筋含量和面筋吸水率的变化,探讨高温密闭储藏下小麦的水分含量与其储藏品质变化的规律。结果表明:35℃条件下,水分含量高的小麦其生活力、过氧化氢酶活动度、湿面筋含量和面筋吸水率降幅大;水分含量为7.7%的小麦电导率增幅最小。     

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。     

Chemical and microbial stability of high moisture dried apricots during storage

BACKGROUND: This study was conducted to determine the chemical and microbial stability of high moisture (HM) dried apricots during storage at 5, 20 and 30 °C for a period of 8 months. HM dried apricots were obtained by rehydrating dried apricots in ‘water’ and ‘water + H₂O₂’. RESULTS: Analysis of kinetic data suggested first‐order models for loss of SO₂ and non‐enzymatic browning reactions. Higher storage temperatures increased the rate of SO₂ loss and formation of brown colour in HM dried apricots. Results from extensive colour measurements (non‐enzymatic browning, reflectance colour and β‐carotene) revealed that the colour of HM dried apricots stored at 5 °C was almost unchanged during 8 months of storage. The colour of samples stored at 30 °C was unacceptable starting from 2 months of storage. Total mesophilic aerobic bacteria counts decreased 0.7, 1.1 and 1.5 log cycles after 8 months of storage at 5, 20 and 30 °C, respectively. For the same storage period, the decrease in mesophilic bacteria was 0.62 log cycle in samples rehydrated in ‘water + H₂O₂’ and stored at 20 °C. CONCLUSION: These results suggest that HM dried apricots should be stored at temperatures lower than 20 °C to preserve the characteristic golden yellow colour. A relatively low level of SO₂ (1458 mg kg^?1 at 200 g kg^?1 moisture level) was sufficient to prevent the growth of spoilage organisms in HM dried apricots at all three storage temperatures. Copyright © 2008 Society of Chemical Industry     

高水分小麦热风干燥后品质的变化

目的：研究干燥工艺对高水分小麦品质的影响。方法：从外观品质、营养品质、加工品质3个维度探究不同干燥工艺下小麦品质变化规律。选取色泽、湿面筋含量、干燥速率3个指标作为响应值,结合响应面分析方法预测高水分小麦的最佳干燥工艺。结果：干燥温度是主要的影响因素。随着干燥温度的升高,小麦色泽加深,粗蛋白含量和湿面筋含量下降,面团的吸水率、形成时间及稳定时间上升,弱化度下降,粉质指数上升,小麦表皮由凸起的小矩形变为凹陷的小坑状,内部淀粉颗粒由光滑的圆形或椭圆形变为粗糙的不规则状。高水分小麦的最佳干燥工艺条件为干燥温度45 ℃,风速0.94 m/s,缓苏时间30.4 min,此时色泽L^*值为58.811、湿面筋含量为27.292%,干燥速率为8.146×10^-2%/min,综合评分为0.613。结论：热风干燥工艺的优化在保证干燥效率的基础上一定程度改善了小麦干燥后的品质。     

Studies on electrical properties of wheat bread as a function of moisture content during storage

Bread undergoes several physicochemical changes during storage that results in a rapid loss of freshness. These changes depend on the moisture content present in the bread product and collectively termed as staling. The present work explains how the electrical properties of bread vary with time and moisture content at its crust and crumb. An instrument based on electrical impedance spectroscopy with multichannel electrodes is developed for the present investigations. Detailed studies have been carried out to understand the influence of changes in moisture profile at bread crust and crumb in terms of electrical properties during the storage of 120 h. A linear relationship is observed between the measured impedance and capacitance and residual moisture content in bread at crust during storage. It is observed that the measured Resistance at bread crumb has a nonlinear mathematical relationship with moisture content present at crumb.     

Dynamics of the particle moisture distribution during storage of wheat under laboratory and pilot-scale conditions

To predict the storability of grain, detailed information is required on the moisture distribution within the grain bulk since a significant variance can be expected in the moisture content between individual grain kernels during storage. Therefore, it is important to consider and determine the single kernel moisture content distribution. The aim of this work was to investigate mass transfer processes that occur during long-term and intermediate storage of grain. For it, the method of particle moisture distribution analysis by means of the Time Domain Nuclear Magnetic Resonance spectroscopy was used. For this purpose, fundamental laboratory-scale experiments were conducted in small storage containers. As these storage experiments revealed, the width of the particle moisture distribution decreased noticeably when there was enough air available in the container for moisture exchange. Thereafter, the storage experiments were extended to pilot-scale using barrels to store grain for months in the scope of about 90 kg per batch. These experiments were performed without ventilation so as to simulate dead zones of airflow that often occur under industrial-scale flat storage conditions. In the closed barrels, no equalization of the particle moisture content was observed even after eleven months of storage. The knowledge gained from the experiments conducted at the micro and meso levels facilitates the understanding of the mass transfer processes that occur during macro scale storage, which are difficult to examine as an entity.     

Effect of storage condition and time on the odor of malathion-treated wheat

Wheat samples treated with premium grade malathion or technical grade malathion were submitted to two different types of sensory panels who were used to discriminate between the odor of treated and untreated wheat.Unselected panelists had difficulty distinguishing treated from untreated grain. Eight panelists selected for their ability to detect insecticide odors in wheat found there was no change in the odor difference between protectant-treated and untreated wheat during 8 weeks storage. However, grain protectant odor seemed somewhat more difficult to detect when the wheat was stored in open containers.A technical grade malathion odor was more obvious in wheat than the premium grade malathion, though the odor of the technical grade malathion decreased markedly over time especially when the treated grain was stored in open containers. In fact, when storage in open containers was used, the patterns of numbers of correct triangular discriminations and ratings of odor difference between treated and untreated wheat were similar for both formulations. A statistically significant proportion of panelists, selected or unselected, never considered the premium grade malathion odor obnoxious.     

淀粉对高水分挤压组织化小麦蛋白产品特性的影响

研究小麦淀粉、马铃薯淀粉、玉米淀粉的添加量对高水分挤压组织化小麦蛋白产品特性的影响。以小麦蛋白为主要原料,采用高扭矩双螺杆挤压装备开发高水分组织化小麦蛋白,并分析了组织化蛋白色泽品质(L~*、a~*、b~*、ΔE)、质构特性(组织化度、硬度、黏着性、弹性、聚结性、咀嚼度)以及感官评价。结果表明:小麦淀粉、玉米淀粉的添加均可显著提高组织化蛋白产品的色泽品质,马铃薯淀粉的添加对组织化蛋白色泽品质影响不显著。淀粉的添加可显著提高组织化蛋白的组织化度。随着淀粉添加量的增加,组织化蛋白质构特性(硬度、弹性、聚结性、咀嚼度)均逐渐降低。添加适量小麦淀粉(5%)、玉米淀粉(5%)均可提高组织化蛋白感官品质,马铃薯淀粉的添加会降低感官品质。综合考虑组织化蛋白色泽品质、组织化度、质构特性和感官品质,添加小麦淀粉(5%)或玉米淀粉(5%)较合适,不仅达到了降低生产成本的目的,而且提高了组织化蛋白色泽品质、组织化度和感官品质。     

高水分小麦通风干燥过程中加工品质变化规律研究

将刚收获的高水分小麦放置在就仓干燥模拟仓内进行通风干燥,测定小麦粮堆各层水分含量变化,及小麦粗蛋白含量、湿面筋含量、粉质特性、降落值等指标。结果表明：含水量超过20%的小麦在模拟仓中采用纵向通风技术可以在短期内将小麦水分含量降低至安全水分,对其加工品质没有显著不良影响。使用通风技术可有效降低小麦水分含量,但各粮层降水存在一定不均匀性,在实仓干燥中可辅以其他技术予以改善。     

Assessing mineral composition and morpho-physiological properties of de-hulled einkorn wheat during storage at different moisture levels

In this study were investigated the effects of different moisture levels (4.8, 9.5, 13, 16.7 and 20%, w.b.) during the storage at 10 °C for three months on some mineral compositions and morpho-physiological properties as dimensional (length, width, thickness, arithmetic mean diameter, geometric mean diameter, surface area and volume, sphericity), gravimetric (thousand grain weight, bulk and true densities) and the seed (colour measurement and electrical conductivity) of de-hulled einkorn wheat seeds. Mineral composition of wheat seeds changed with increasing moisture level. In particular, decreases in mineral composition were observed above 16.7% moisture level. Dimensional properties showed increases depending on increased moisture level. It was found that thousand grain weight and true density values increased with increase in moisture level. However, bulk density values were found to decrease with increase in moisture level. The seed colour properties as L*, a*, b*, Chroma, hue angle and Browning index did not change statistically at the end of three months storage with increase at moisture level. The results showed that mineral compositions and functional properties of seeds at moisture level of 9.5% is more suitable than other moisture levels. As a result, high moisture levels during storage can cause degradation of seed quality.     

不同储藏方式对小麦粉水分、脂肪酸值和白度的影响

研究了在25℃条件下,不同储藏方式对小麦粉水分、脂肪酸值和白度的影响.结果表明:不同储藏方式对小麦粉水分均有一定影响,低温冷冻储藏的小麦粉水分随着储藏时间延长而逐渐升高;在其他储藏方式下,小麦粉水分随着储藏时间的延长均有一定程度的下降.在不同储藏方式下,随着储藏时间的延长,小麦粉脂肪酸值均呈上升趋势.添加脱氧剂的气调包装可以加速小麦粉白度的变化,其他储藏方法对小麦粉白度的影响不显著.     

Effect of controlled atmosphere storage on aflatoxin production in high moisture peanuts (groundnuts)

Shelled peanuts (groundnuts) remoistened to 16.7% were stored for 4 weeks at about 27°C in air (0.03% CO₂, 21% O₂, 78% N₂) and in three modified atmospheres: (1) 13.6% CO₂, 0.3% CO, 0·6% O₂, 84.7% N₂; (2) 12.2% CO₂, 3.1% CO, 0.3% O₂, 83.5% N₂; and (3) 13.6% CO₂, 0.1% CO, 1.5% O₂, 83.9% N₂. Aflatoxins, per cent free fatty acids, and per cent kernel infection by the Aspergillus flavus group were determined weekly. Peanuts in air and in the atmosphere containing 1.5% O₂ accumulated high levels of aflatoxin in 1 and 2 weeks, respectively. In the other two controlled atmospheres aflatoxin B₁ did not exceed 21 μg/kg and the per cent of free fatty acids increased only slightly. None of the treatments eliminated infection by the A. flavus group. After 4 weeks peanuts in all treatments had visible fungal growth on surfaces.     

Effect of moisture and temperature on storage changes in lipids and carotenoids of atta (wheat flour)

Effect of moisture and temperature on changes in total carotenoids, fat acidity, free and bound lipids and their composition taking place during storage of atta are reported. At moisture contents of 10.4% and below, increase in fat acidity results mainly from hydrolysis of neutral lipids; phospho- and galactolipids are not hydrolyzed to a significant extent. At moisture level of 11.6% and above both phospho- and galactolipids are degraded to a significant extent. At moisture levels of 12.9% and above mould growth ensues which greatly accelerates the rate of degradation of both polar and non polar lipids. Degradation of carotenoids also increases with increase in storage temperature and moisture content from 9.4 to 16%.     

不同包装方式对高含水量萌芽糙米储藏的影响

将高水分含量(25±1）%的发芽糙米分别用PE袋自然包装、充入CO2和N2包装,纸袋自然包装和纳米包装袋自然包装5种包装方式在25 ℃条件下储藏90天,研究了这5种包装方式的发芽糙米在贮藏过程中的霉菌总数、还原糖、可溶性蛋白、游离氨基酸、脂肪酶活力、脂肪酸、丙二醛及表面颜色(L*值、C*值和H°值)的变化。结果表明：PE袋气调包装和纳米包装袋自然包装的效果明显优于纸袋包装,其中PE袋充N2包装储藏效果最佳,PE袋充CO2包装和纳米包装效果次之。     

储藏时间对大豆蛋白和谷朊粉的结构及功能特性的影响

为了探究储藏过程中组织化植物蛋白原料性质的变化,本研究对大豆分离蛋白（SPI）、大豆浓缩蛋白（SPC）和谷朊粉（WG）三种主要蛋白原料进行加速储藏实验,测定储藏过程中原料的羰基含量、巯基及二硫键含量、表面疏水性、溶解度、持水性、持油性和吸水率的变化。结果表明：到储藏期结束,SPI和SPC羰基含量大约分别增加144%和130%,游离巯基含量则在加速储藏15天显著降低,大约分别减少62%和67%;WG的羰基含量大约增加45%,游离巯基含量在储藏过程中缓慢下降,大约减少15%。随着储藏的进行,三种蛋白的二硫键含量和表面疏水性均先增加后降低,功能特性上SPI和SPC的溶解度分别从88.67%、78.69%降低到42.36%、25.22%,而WG溶解度却从6.78%增大到8.48%;三种蛋白质持水性均降低,其中SPC持水性下降程度大,达30%,WG吸水率没有显著性变化;SPI和WG的持油性先升高后降低,SPC的持油性则在加速储藏75天时出现显著性下降。这说明储藏期内蛋白质发生氧化反应,导致蛋白结构和功能特性发生变化,最终将影响组织化蛋白的品质特性。     

空调控温技术在偏高水分稻谷储藏中的应用

针对稻谷的储藏不稳定性,利用空调对高大平房仓散存偏高水分稻谷进行仓温控制,把粮堆表层平均粮温控制在20℃以内,创造准低温的储粮环境,有效控制稻谷表层粮温的上升,抑制虫霉繁殖,减少储粮污染,保证储粮品质,减少水分损耗,增加储粮经济效益和社会效益。     

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.     

Safe storage of maize in alternative hermetic containers

Purdue Improved Crop Storage (PICS) bags have been developed and extended as a way to address grain storage issues faced by smallholder farmers in developing nations. A hermetic technology, PICS bags reduce insect damage to grain significantly while maintaining its quality for many months or longer. Farmers with varying and often small volumes of grain at harvest, may still benefit from alternatives to PICS bags for storing their grain. We evaluated plastic bottles, which may be hermetically sealed, for storing maize grain. Clean maize grain was stored for eight months in sealed and unsealed plastic bottles with half of these bottles being infested by maize weevil (Sitophilus zemais, Motschulsky). Oxygen levels in the bottles were monitored throughout the trial and grain was assessed for moisture content, insect damage, germination rate and insect population size when the study was terminated. Sealed bottles preserved grain quality significantly better than unsealed, infested bottles and as well as non-infested unsealed containers. Plastic soda bottles can be used as hermetic containers for safely storing grain.