优质籼米地下仓储藏过程中品质变化

为探索成品粮绿色、安全的储藏方法,在南方高温高湿地区,利用地下仓储藏黄花粘和籼优998两种优质籼米,定期检测水分、碎米总量、小碎米率、垩白粒率、黄粒米、直链淀粉、品尝评分值、色泽气味、不完善率、害虫虫口密度等指标。实验结果显示,实验期间,大米水分呈小幅下降;2种大米不生虫时间长达13个月;小碎米率、色泽气味等指标无显著性变化;碎米总量、黄粒米、不完善粒含量小幅增加,直链淀粉含量逐渐增加,但均未导致大米质量等级下降;垩白粒率显著增加,品尝评分值显著下降,且均造成大米质量定等下降。根据国家标准《大米》的规定,籼优998于储藏3个月后,质量定等由二级降为三级,储藏6个月后,已不属于优质籼米,黄花粘于实验结束后仍为优质籼米三级。说明地下仓具有良好的保湿、保鲜和害虫抑制效果,优质籼米耐储性能与储藏条件和品种均相关。     

Micromechanical properties of almond kernels with various moisture content levels

Almond fruits are subjected to various mechanical stresses throughout production, from harvest to processing, storage and packaging. Kernel properties play an important role in reducing mechanical damage such as scratches and penetration of shell pieces. Knowledge of kernel properties under various conditions of the fruit can assist in optimising post-harvest and processing lines to minimise kernel damage and thus maximise final kernel quality. Kernel moisture content is one of the main attributes affecting the kernel’s response to mechanical processing. Increasing the kernel moisture content to an optimum level through wetting fruit prior to processing can lead to a reduced percentage of damaged kernel. Water added to the structure of kernels acted as a plasticiser and helped the kernels to absorb the mechanical load instead of fracturing and breaking into pieces. In this study, tests were conducted on almond kernels with different moisture content levels from 5.52 to 14.09g/100g wet basis. Kernels from a Nonpareil variety were tested in dried and wetted conditions. Test results showed that kernels with higher moisture content were able to undergo a larger deformation at a given force value in comparison with dry kernels. Average deformation for dry samples was from 0.12 mm, which increased to an average of 0.25 mm in wetted samples. The effect of skin on the mechanical properties of the kernels (with and without skin) was studied using a mechanical tester. The test results showed a peak force value in samples tested with skin in comparison with the kernels tested without skin.     

The Effects of Damaged Kernel Caused by Combine Harvester Settings on Milled Rice Free Fatty Acid Levels

Milled rice surface oil and free fatty acid (FFA) contents determine rice acceptability to the brewing industry. Both could subsequently contribute to beer off‐flavors and thus compromise milled rice brewing quality. Controlling milled rice FFA by harvesting practices could be important in maintaining brewing quality as some rough rice is damaged by hull removal and/or bran disruption during harvesting. To determine the effect of harvester speed on kernel damage, the long‐grain rice variety Cocodrie was harvested at 3 different combine harvester settings and the percent of damaged kernel (w/w) was measured. Combine harvester cylinder speed had a significant effect on rough rice kernel damage. The percentages of damaged kernels for 550, 850, and 1000 rpm cylinder speeds were 1.2%, 4.0%, and 9.0%, respectively. The FFA level of milled rice with varying amount of damaged kernels was investigated over 6 mo of storage. The faster harvester cylinder speeds resulted with time in significantly greater FFA levels in “as‐harvested” rice. The FFA content of 1000 rpm as‐harvested rice almost reached the 0.1% (w/w) level. The greater the amount of damaged kernel, the greater was the milled rice FFA level, and it was significantly greater than milled rice with no damaged kernels during accelerated storage. The as‐harvested rice with 1000 rpm had the highest FFA level, followed by 850 and 500 rpm.     

Hull characteristics as related to susceptibility of different varieties of rough rice to Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

Rhyzopertha dominica (F.), an important pest of stored grains, causes economic damage to rough rice through physical damage to the kernel, resulting in reductions in grain quality. In this test, 28 varieties of commercial rough rice (10 long grain, 11 medium grain, and 7 short grain) were examined for solid, split and cracked hulls, hull thickness, and adult emergence from neonate R. dominica introduced on each individual variety. The percentage of solid hulls ranged from 55.5% on Koshihikari variety to 92.8% on Akita variety, and the percentages of cracked and split hulls were correlated with increased susceptibility. The Dobie index for progeny production showed Wells, Jupiter, and Pirogue varieties as the most tolerant to R. dominica, while Rico and Francis were the most susceptible. The hull thickness of rough rice varied among varieties, but the tolerant varieties appeared to have thicker hulls than the susceptible varieties. There was no difference among rice types (long-, medium-, or short grain) regarding tolerance or susceptibility to R. dominica. Results show that the characteristics of the rough rice hull are important for conferring susceptibility of individual varieties to R. dominica.     

Identification of Broken Rice Kernels Using Image Analysis Techniques Combined with Velocity Representation Method

The percentage of whole kernels remaining after milling is one of the most important physical characteristics of rice quality. A method based on flatbed scanning and image analysis was developed for the identification of broken rice kernels. Velocity representation method was developed for pattern recognition based on the contour characteristics of the rice kernels. The similarity of the boundary features of the image of rice kernel was measured by similarity coefficient, which was used to identify the broken rice kernel by comparing with threshold. High recognition rates for three rice varieties were reached by this method with 96.7% for Thailand rice, 98.73% for Pearl rice, and 97.14% for Changlixiang rice, respectively, and the recognition rate could be improved by the adjustment of the similarity coefficient threshold. Because the comprehensive boundary features were the basis for the classification, this method could be more accurate compared to other methods using the single dimension feature.     

日本の寒地，北海道のうるち米における白未熟粒発生を抑制する栽培法（日文）（网络首发、推荐阅读）

白未熟粒の多発生は,整粒歩合を低下させ検査等級を下げるため,抑制する必要がある。白未熟粒,その中でも乳白粒と基部未熟粒の発生率に品種間差異があった。白未熟粒は,止葉切除による光合成の減少,増肥とそれによるm2当たり籾数の増加,疎植および育苗時の高温で生じる早期異常出穂による穂揃い不良,および刈り取り時期の遅延により増加した。倒伏により青未熟粒?白未熟粒は多くなった。初期生育が良好な場合,分げつ期からの深水灌漑は過剰分げつ発生を抑制し,粒重と玄米収量を増加させ,玄米品質も向上させた。登熟期の土壌の過乾燥により,腹白粒発生による品質低下や千粒重減少による減収を生じた。これら白未熟粒の発生は,出穂期から出穂揃い期10日後までの茎葉から籾への非構造性炭水化物（NSC）の1籾当たり転流量および粗玄米収量から同転流量を減じた1籾当たりNSC増加量が多いほど,少なかった。白未熟粒の多発生回避には,施肥量,栽植密度,育苗ハウスの温度管理,移植時期,登熟期の土壌水分および刈り取り時期を適正化し,初期生育を促進し,過剰分げつを深水で抑制する必要があった。以上の栽培法改善と,1990年代後半以降からの共同乾燥調製貯蔵施設での色彩選別機を使った1等米調製により,北海道の1等米比率は全国平均を上回るようになった。     

Susceptibility of commercial oat cultivars to Cryptolestes pusillus and Oryzaephilus surinamensis

Susceptibility to two storage insect pests [(Cryptolestes pusillus (Schönherr) and Oryzaephilus surinamensis (L.)] of eight commercial oat cultivars from the United States was determined in laboratory studies. Duration of insect development was shorter and number of progeny produced was greater on cracked than on whole oats. Simulations based on data from the study showed that insect populations would reach the threshold level for treatment in 2-3 months of storage at 30°C on cracked oats. Insect population development was slowest on the hulless cultivar Paul when the oat kernels were cracked. Simulations also indicated that all cultivars of whole oats tested could be stored for at least 1 yr at 30°C without reaching the threshold for treatment when infested with these two species of insects, and insect populations would decrease over time on the cultivars Don, Jerry, Milton, NewDak, Otana, and Valley. Analyses of oat grain quality characteristics, including kernel weight, groat hardness, and groat composition, provided little insight into the mechanism of observed differences in insect development among cultivars. Hardness of the kernels (as indicated by % broken groats after dehulling) may be related to near immunity to these two species of insects in whole Otana. Steaming whole oats to inactivate hydrolytic enzymes in the trichomes of the pericarp did not increase susceptibility to these two species of insects, suggesting that enzymes in the trichomes were not responsible for insect population development being slower on whole oats than on cracked oats. Although we were unable to identify the factors that determined relative susceptibility in this study, the results will be useful for selecting commercial oat cultivars for planting that will be less susceptible to insect pests in storage and suggest that the economics of cleaning oats before storage to reduce insect population growth should be investigated.     

日本寒冷地带北海道抑制粳稻生成白未熟粒的栽培法（网络首发、推荐阅读）

白未熟粒的多发会使整粒率下降,降低检查等级,因此急需抑制其发生。白未熟粒中,乳白粒和基部未熟粒的发生率存在品种间差异。切除止叶减少光合作用,增肥导致每平方米稻谷数量的增加,疏植和育苗时高温引起早期异常抽穗所致的齐穗不良,以及收割时期的延迟等会造成白未熟粒的增多。此外倒伏还会导致青未熟粒、白未熟粒增多。在初期生长良好的情况下,从分蘖期开始的深水灌溉抑制了过剩的分蘖产生,增加了粒重和糙米产量,使糙米品质得以提高。由于成熟期的土壤过于干燥,因腹白粒产生引起的品质降低和千粒重减少会导致减产。从抽穗期到齐穗期10天后的茎叶到稻谷的每粒稻谷非结构性碳水化合物（NSC）流转量,以及粗糙米产量减去同一流转量的每粒稻谷NSC增加量越多,这些白未熟粒的产生就越少。为避免白未熟粒的多发,必须使施肥量、种植密度、育苗温室的温度管理、移植时期、成熟期的土壤水分和收割时期合理化,促进初期生长,用深水抑制过剩的分蘖。通过改善以上的栽培方法,以及1990年代中期后在共同干燥调制储藏设施中使用色选机选别糙米,北海道的一等米比例超过了日本全国的平均水平。     

含水量对小麦麦仁膨化品质的影响

分析了小麦麦仁的含水量对麦仁膨化品质的影响,为小麦麦仁的精深加工提供科学依据。将小麦麦仁含水量调节到8%,10%,12%1,4%,16%,18%和20%7个水平,测定麦仁膨化品质。结果表明,在小麦麦仁品质和膨化压力等因素一致的条件下,小麦麦仁含水量对麦仁膨化品质的影响非常明显。最大的膨胀体积,鳞片大小和最小的未膨胀率在麦仁分含水量为16%取得。另外,膨化后的麦仁粉峰值黏度,谷值黏度,末值黏度,衰减值和回生值都比未膨化麦仁粉低,膨化后的麦仁粉凝胶硬度和咀嚼性比原麦仁粉降低。     

Nutritional composition of Canarium pimela L. kernels

The kernels of Canarium pimela L., obtained from Guangdong Province, PR China, were analysed for their proximate composition, fatty acid composition, amino acid profile and mineral contents. The kernels were abundant in fats (59.7%) and proteins (23.9%). The acid, iodine, and saponification values of the kernel oil were 0.33, 92.4 and 191, respectively. Oleic acid (43.0%) and linoleic acid (26.5%) constituted the main unsaturated fatty acids of the kernel oil, while palmitic acid (24.8%) was the major saturated fatty acid. The kernel proteins were rich in glutamic acid, arginine and aspartic acid (21.0%, 12.5%, and 6.80%, respectively), but not the limiting amino acid lysine (2.37%). The mineral elements were also involved in this study. The results indicated that C. pimela L. kernels may be a potential source of oil or protein for the human diet.     

Influence of maize kernel state and type on life history of Plodia interpunctella (Lepidoptera: Pyralidae)

The objective of this study was to investigate the influence of different mechanical states (whole, broken and ground kernels) and types (dent, semi-flint and flint) of maize kernels on life history parameters of Plodia interpunctella (Hübner), the Indian meal moth. These parameters included larval development and its dynamics, adult emergence, mean development duration (MDD) and fecundity. Since the larvae are the developmental stage that causes the most damage on maize, additional data on larval development helps identify conditions that promote development. The results of our study indicate that broken maize kernels are the most suitable for P. interpunctella development, where the most successful larval development, the highest number of emerged adults, the shortest MDD and the highest total fecundity were recorded. On the contrary, whole kernels were the least suitable and the most resistant to infestation by P. interpunctella. The type of kernel also significantly affects P. interpunctella developmental parameters. Females reared on flint kernels (the hardest kernel type tested in our study) laid the largest total number of eggs, which implies that kernel hardness, i.e. the type of kernel should be an important parameter when choosing maize hybrids for cultivation and for storage. Our study warrants further investigation of maize types and their susceptibility to P. interpunctella.     

Estimating deoxynivalenol contents of wheat samples containing different levels of Fusarium-damaged kernels by diffuse reflectance spectrometry and partial least square regression

Fusarium head blight is a fungal disease causing yield losses and mycotoxin contamination in wheat and other cereals. Wheat kernels (cultivar Ritmo) were sampled in 2001, 2002, 2003, and 2006 and Fusarium-damaged kernels were separated from sound grain based on visual assessment. Subsequently, grain lots containing 0, 20, 40, 60, 80, and 100% of damaged kernels were compiled. Each lot was split and the spectrometric reflectance (wavelengths 350-2500 nm) was measured using subgroup one, while the concentration of the mycotoxin deoxynivalenol (DON) was determined by high-performance liquid chromatography in subgroup two. DON concentrations in batches classified as sound were not significantly different from 0. Estimating DON contents from the percentage of Fusarium-damaged kernels was impeded by vast variability, resulting in a coefficient of determination of 0.49. Using spectrometric data subjected to partial least square regression allowed estimating DON contents with higher accuracy, in particular at elevated percentages of damaged kernels. The coefficient of determination was 0.84 for the relationship between DON contents estimated based on spectrometric data and the DON contents measured. The intercept of a regression line fitted through a plot of estimated versus measured DON contents was 0.89 ± 3.61 mg/kg. Since intercept + standard error was larger than the actual legal limit (1.25 mg DON per kg dry grain in the European Union), the spectrometric procedure was still not precise enough to allow a reliable separation of grain samples with DON contents below 1.25 mg/kg from samples with DON contents above the limit. However, spectrometric data also allowed estimating the DON content of the average damaged kernel within a given lot composed of sound and damaged kernels, which is probably the reason for the reduction of the fraction of unexplained variance by 35% compared to the visual approach and illustrates that spectrometric approaches can make a contribution to reducing DON contents of wheat grain.     

酶法制备米糠分离蛋白的研究

选用细胞破壁酶类和蛋白酶类来提取米糠蛋白,从两类酶中分别选出最佳用酶及酶用量。实验表明,纤维素酶是最佳的细胞破壁酶,其最佳添加量为:[E]/[S]=2%。复合蛋白酶为最佳蛋白酶用酶,其最佳添加量为:[E]/[S]=5%。     

Fungi,mycotoxins and phytoalexin in peanut varieties,during plant growth in the field

The aim of the present study was to analyze the mycobiota, occurrence of mycotoxins (aflatoxins and cyclopiazonic acid), and production of phytoalexin (trans-resveratrol) in two peanut varieties (Runner IAC 886 and Caiapó) during plant growth in the field. Climatic factors (rainfall, relative humidity and temperature) and water activity were also evaluated. The results showed a predominance of Fusarium spp. in kernels and pods, followed by Penicillium spp. and Aspergillus flavus. Aflatoxins were detected in 20% and 10% of samples of the IAC 886 and Caiapó varieties, respectively. Analysis showed that 65% of kernel samples of the IAC 886 variety and 25% of the Caiapó variety were contaminated with cyclopiazonic acid. trans-Resveratrol was detected in 6.7% of kernel samples of the IAC 886 variety and in 20% of the Caiapó variety. However, trans-resveratrol was found in 73.3% of leaf samples in the two varieties studied.     

Nutritional composition of the kernels from Canarium album L.

The kernels from Canarium album L. (also called Chinese olive), largely cultivated in the southeast of China, were analyzed for their nutritional composition. The kernels had a high percentage of fats (52.8%) and proteins (29.5%). Soxhlet extracted kernel oil presented acid, iodine and saponification values of 0.56, 84.6 and 192, respectively. Gas chromatography–mass spectroscopy (GC–MS) analysis of kernel oil revealed that oleic acid (30.5%) and linoleic acid (41.8%) were the major unsaturated fatty acids, while palmitic acid (18.0%), stearic acid (7.83%) and arachidic acid (0.39%) were the main saturated ones. Potassium, calcium and magnesium were the predominant mineral elements present in the kernels. Sodium, iron, manganese and zinc were also detected in appreciable amounts. The kernel proteins were rich in arginine, glutamic and aspartic acids (3.19%, 5.02% and 2.47%, respectively) while the limiting amino acids were methionine and lysine.     

Effect of drying and tempering on rice fissuring analysed by integrating intra-kernel moisture distribution

The fissure generation of one short- and two long-grain rough rice dried at different air conditions for 15, 30 and 60 min, and respectively, tempered at 20, 30, 40 and 50 °C for tempering duration ranging from 0 to 330 min was analysed by integrating moisture gradients in rice kernels. Results indicated that drying and tempering processes had significant effects on the moisture gradient and rice fissuring. The percentage of fissured kernels increased with increasing drying time and decreasing tempering time. The tempering duration required for long-grain rice was shorter than that for short-grain rice to prevent kernel fissuring. Higher tempering temperatures can effectively eliminate moisture gradients and then lower the rice fissuring generation. Tempering at 50 °C reduced fissuring incidence by 32 to 50% compared to tempering at 20 °C. Moreover, short-grain rough rice was very susceptible to fissure whereas long-grain rough rice with a high amylose content was much more fissure-tolerance.     

Survey of Salmonella contamination of edible nut kernels on retail sale in the UK

Consumption of nut kernels has shown an upward trend due to people's increasing tendency to eat healthy snacks. The purpose of this survey was to establish the microbiological safety of retail edible nut kernel samples of different varieties. Overall Salmonella spp. and Escherichia coli were detected from 0.1% and 0.8% of 2886 edible nut kernels, respectively. S. Senftenberg and S. Tennessee were detected from two pre-packed samples of Brazil nuts (0.4%) and S. Anatum from a pre-packed mixed nuts sample (0.9%; mix: almonds, Brazils, cashews, peanuts, walnuts) indicating a risk to health. The levels of Salmonella ranged from <0.01 to 0.23/g. E. coli at unsatisfactory levels (150/g) was present in another pre-packed Brazils nuts sample (0.2%). E. coli was additionally found at lower levels (range: 3.6–43/g) in Brazils (1.9%), macadamia (1.5%), pistachios (1.1%), walnuts (0.7%), peanuts (0.7%), hazels (0.5%), cashews (0.4%), and almonds (0.3%). Levels of E. coli did not correlate with the presence of Salmonella. The batches contaminated with Salmonella were recalled and Food Standards Agency food alerts were issued to advise against the consumption of the affected products. The presence of Salmonella is unacceptable in ready-to-eat foods and follows that the need for applying good agricultural and hygiene practices and effective decontamination procedures during the production of edible kernels cannot be overemphasized.     

Effect of Pisum sativum fractions on the mortality and progeny production of nine stored-grain beetles

Yellow field pea (Pisum sativum L.) fractions that were mainly protein (50%), fibre (90%) or starch (85%) were obtained from a commercial pea mill and mixed with wheat kernels or wheat flour. Based on the mortality and the number of offspring produced, protein-rich pea flour was more toxic than fibre, which was more toxic than starch. For the protein-rich pea flour mixed with wheat kernels, the most sensitive insects were Sitophilus oryzae (L.), Sitophilus zeamais Motschulsky and Sitophilus granarius (L.), followed by Cryptolestes ferrugineus (Stephens) which was more sensitive than Tribolium castaneum (Herbst) and Rhyzopertha dominica (F.). For the protein-rich pea flour mixed with wheat flour, Cryptolestes pusillus (Schönherr) was most sensitive, followed by C. turcicus (Grouvelle) and T. confusum (Jacquelin du Val), with T. castaneum being the most resistant. Although protein-rich pea flour did not kill adults to a great extent when mixed with flour, it reduced offspring production significantly. Again C. pusillus was the most sensitive, followed by T. confusum, with T. castaneum offspring being the most resistant. The insecticidal activity of pea fractions decreased after treated wheat kernels were held at 30 °C, 70% r.h. for 8 months. The potential of using pea fractions to control stored-product insects is discussed.     

Antioxidant and antimicrobial activity of guarana seed extracts

The antioxidant and antibacterial activities of guarana (Paullinia cupana) seed extracts were determined. The seeds were extracted with water, methanol, 35% acetone and 60% ethanol at room (T_R) and at boiling (T_B) temperature of solvent.     

Water migration mechanisms in amorphous powder material and related agglomeration propensity

The agglomeration phenomenon of amorphous particulate material is a major problem in the food industry. Currently, the glass transition temperature (T_g) is used as a fundamental parameter to describe and control agglomeration. Models are available that describe the kinetics of the agglomeration process as a function of the distance of the material from T_g (i.e. T − T_g). In practice these models are often not applied because they assume that the powder material is instantly in equilibrium with the humidity conditions of the environment and that solid mobility only occurs at T > T_g. Insights in the kinetics and mechanisms of water transport in powder material can help to better understand and control powder agglomeration. For this purpose, gravimetric step-change water sorption experiments were performed on maltodextrins as a function of the water activity a_w. The maltodextrins vary in dextrose equivalents (DE), particle size and morphology. The experimental results were compared with a Fickian diffusion model in order to understand the dependency of the transport mechanism on water concentration gradient and material relaxation. The water transport kinetics in the maltodextrins with low DE (i.e. 6) were well described by Fickian diffusion for low a_w, independently of particle size and morphology, until relaxation phenomena started to occur at an a_w corresponding to T − T_g = −20 °C. The importance of the matrix relaxation phenomena on the water transport mechanism increased with increasing DE (i.e. 29 and 32), not showing any relationship with the T_g. The results of this study indicate that the water migration mechanism is controlled by relaxation phenomena when the amorphous material is still far from the glass–rubber transition. The T − T_g at which the relaxation phenomena occur depends on the material. On the contrary, the T − T_g parameter could well describe the onset of agglomeration, independently from the material properties. Therefore, it can be concluded that within the conditions of this study, matrix relaxation occurring far below T_g did not affect the onset of agglomeration.