PH—Postharvest Technology: Airflow induced by Falling Cottonseed Particles

Bulk materials falling freely in a chute draw air with them. Experiments were carried out to study the parameters that influence the induced airflow. The bulk material consisted of fuzzy and delinted cottonseeds and hulls. The experimental equipment included a loading, open hopper and an unloading enclosure connected to a chute. An orifice flowmeter was provided in the enclosure wall. The air drawn into the enclosure left it through the flowmeter orifice. The parameters varied during the experiments were the kind and the flow rate of falling particles, and the length, cross-section and slope of the chute. The measured data showed that the airflow rate grows with increasing chute length, cross-section or slope. The airflow rate also increased with the fuzziness of the cottonseed and decreased as the particles' terminal velocity increased. Dimensional analysis was used to formulate an approximate form of the law governing the process. It was found that the terminal velocity of the falling particles characterizes well their aerodynamic properties. Graphs plotted in accordance with the law developed in this work compared favourably with most measured data.     

PH—Postharvest Technology: Dielectric Properties of Common Bean

This paper discusses the variation of relative permittivity, dielectric loss factor, loss tangent, and a.c. conductivity of common bean, Phaseolus vulgaris L., variety Campeão-3 from 75 kHz to 5 MHz. Included are curves showing the variation of these dielectric properties on moisture and bulk density. The variation of relative permittivity on frequency, moisture content, and density was more regular compared to the behaviour of the other dielectric properties in that it continuously increases with moisture and bulk density and decreases with frequency. The conclusion is that of all dielectric properties the relative permittivity should provide less error in common bean moisture content determination.     

PH—Postharvest Technology: Physical Properties of Okra Seed

The physical properties of okra seed were evaluated as a function of moisture content (m.c.). The average length, breadth and thickness of the seed varied from 5·92 to 7·30, 4·71 to 5·40 and 4·59 to 5·36 mm, respectively, as the moisture content increased from 8·16 to 87·57% d.b. The roundness and sphericity increased from 77·76 to 79·35% and 74·48 to 76·52%, respectively, with increase in moisture content from 8·16 to 19·56% d.b. and then decreased to 72·39 and 70·63%, respectively, with further increase of moisture content. In the moisture range of 8·16–87·57%, the seed volume increased from 0·067 to 0·124 cm³, 1000 seed weight, W₁₀₀₀ from 65·78 to 129·75 g and the angle of repose from 27·60 to 39·47°. The bulk density, true density and porosity decreased from 0·592 to 0·558 g cm⁻³, 1·107 to 0·986 g cm⁻³ and 46·34 to 43·20%, respectively, in the moisture range from 8·16 to 87·57% d.b. The static coefficient of friction increased on four structural surfaces namely, aluminium (0·390–0·484), bakelite (0·345–0·480), galvanised iron (0·368–0·493) and mild steel (0·389–0·480) as the moisture content increased from 8·16 to 87·57% d.b.     

PH—Postharvest Technology: Thermodynamics of Moisture Sorption in Sesame Seed

Experimental data on the sorption isotherms of sesame seed were used to determine the thermodynamic functions (heat of vaporisation, spreading pressure, net integral enthalpy and entropy). The heat of vaporisation decreased with increase in moisture content and approached the latent heat of pure water at moisture content between 18 and 21% dry basis. The spreading pressure increased with increase in water activity and was not significantly affected by temperature. Net integral enthalpy decreased with increase in moisture content, and became asymptotic as the moisture content of 12% was approached. Net integral entropy decreased with increase in moisture content to a minimum value of 0·138 J kg⁻¹K⁻¹ at moisture content of about 3·7%. It then increased with moisture content to a maximum of about 0·63 J kg⁻¹K⁻¹ at about 12% moisture content and thereafter, remained nearly constant.     

PH—Postharvest Technology: Surface Gloss and Weight of Eggplant during Storage

Surface gloss and weight loss are two important parameters to judge the freshness of eggplant. Data were collected in order to develop some quick and reliable instrumental methods to determine these. Surface gloss and weight loss of eggplant stored for 0–96 h at 80–84% relative humidity and 20°C temperature were determined using a computerized spectral radiometer and a precision electronic balance, respectively. The surface gloss was quantified in terms of gloss index, and a relationship between weight and gloss index during storage of eggplant was established. Gloss index and weight both decreased quadratically with storage period. Major changes were observed in the first 48 h of storage. Weight and gloss index of eggplant during storage were found to be correlated linearly.     

PH—Postharvest Technology: Automatic Jalapeño Chilli Grading by Width

Jalapeño chilli is a variety grown extensively in Mexico consumed by almost all the population. It has a high processing demand and proper sorting is required before filling or canning. A sorter that classifies chilli by three different width sizes was built. The conveyor used baby suckers to align each chilli during sensing. Chilli width was determined by means of a photodiode scanner, which detected the incoming radiation sent by a laser line generator. Chillies presenting necrosis were detected with a radiometer and removed to increase product quality. The accuracy on the necrosis detection and width classification was of 96·3 and 87%, respectively.     

PH—Postharvest Technology: Some Aspects of the Mechanical Properties of Shea Nut

Compression tests were carried out on pre-treated shea nuts to study the effects of moisture content, temperature and loading position on rupture force, deformation, toughness and firmness at the point of failure. All factors were examined and most of their interactions had significant effects on the measured para-meters at 0·05 level of significance. Rupture force and firmness decreased while deformation and toughness increased with increases in moisture content in both horizontal and vertical loading positions. The results provide useful data to be used by engineers in the design of suitable shea nut cracker.     

PH—Postharvest Technology: The Effects of Grain Temperature on Breakage Susceptibility in Maize

To understand the viscoelastic characteristics (i.e. hardness) of the maize (Zea Mays L.) grain in relation to high-temperature drying, a breakage tester (HT-I drop tester) was developed and single-grain breakage at various grain temperatures and times after drying was determined. Both hard and soft maize hybrid varieties had minimal breakage at high grain temperatures (78–110°C), while decreasing grain temperature increased breakage exponentially. After drying at both 60 and 120°C, the percentage breakage measured at ambient temperature increased rapidly during cooling in air at an ambient temperature of 20°C and a relative humidity in the range 65–70%. Breakage reached a maximum after about 10 min from the start of cooling. A Mitscherlich function described the chronological development of percent grain breakage. Analysis of the function parameters for the extent (maximum) and rate of breakage indicated that there was a significant interaction between variety and drying temperature for the development of grain breakage after drying. These results indicated that grain temperature should be considered as a co-factor when assessing grain breakage susceptibility.     

SE—Structures and Environment: Compost Airflow Resistance

Four bulking agents, pine shavings, mixed (long and chopped) grass hay, chopped grass hay and long (whole) wheat straw, were each mixed with pig slurry and tap water to obtain three moisture contents (MC) of 60, 65 and 70%. Quadruplets of each treatment were placed in laboratory composting vessels with a capacity of 105 l and a composting depth of 0·95 m. Using the air plenum at the bottom of each vessel, air was forced at apparent velocities of 0–0·002 m s⁻¹ through each compost mass to measure the air static pressure drop across the compost mass as a function of apparent air velocity. Airflow resistance values were measured for compost depths ranging from 0·55 to 0·85 m. Following this test, all mixtures were aerated for 21 days of composting without overturning. The static pressure measurement procedure was then repeated on all quadruplet mixtures.The air static pressure drop was found with respect to a packed bed under laminar flow, defined using the particle size distribution, porosity, depth and airflow channel characteristics of the compost material. Although MC affected the value of the airflow channel characteristics of the compost material, both the hay and straw demonstrated similar values, while shavings demonstrated values more variable and wider values for MC between 60 and 70%.There was a significant increase in airflow resistance after 21 days of composting, which supports the need for compost overturning to reestablish the material's structure and to restore the airflow channels or pores.     

Soil Boron Fractions and Response of Green Gram in Calcareous Soils

A greenhouse experiment with green gram on boron (B) deficient calcareous soils was conducted for two years at Ludhiana (Punjab), India to study soil B fractions and response of green gram to B application. Three soils with calcium carbonate (CaCO₃) content 0.8 (Soil I), 2.1 (Soil II) and 4.6 (Soil III) percent were collected from different sites of Ludhiana and Bhatinda districts, Punjab, India. The treatments comprised of five levels of soil applied B (0, 0.5, 0.75, 1.0, and 1.5 mg B kg^?1). The experiment was laid out in completely randomized design (CRD) factorial design with three replications. Readily soluble B comprised 0.39 to 0.76 percent in Soil I, 0.32 to 0.54 percent in Soil II, and 0.21 to 0.34 percent in Soil III of the total B, taking into account of all the levels of B applied at both stages of crop growth. Readily soluble B increased with increasing application rates of B and decreased from grand growth stage (40 days after sowing) to maturity of the crop. Specifically adsorbed, oxide bound, residual, and total B was higher in Soil III as compared to Soil II or Soil I. At maturity, specifically adsorbed B converted into other fractions to maintain equilibrium in soil solution. Organically bound B was greater than oxide bound B. Among all fractions, the residual fraction accounted for the major fraction of the total B. Soil application of lowest level of B was adequate to cause significant increase in dry matter yield and seed yield of green gram regardless of type of soil.     

Effect of Digestive Enzyme Treatment on Antioxidant Properties of Germinated Green Gram Fortified with Minerals

The antioxidant activity (AA) of green gram germinated in mineral‐fortified water (with iron at 100 or 200 mg/100 mL or zinc at 50 or 100 mg/100 mL), cooked under pressure (PC), or microwaved and subjected to digestive enzyme treatment was determined by using three assay methods. Total AA showed that dehulled grains (DG) had higher AA than whole grains (WG). Cooking reduced the AA in both methods compared with raw grains with a lower percent retention of AA, although significant variations were not found between methods. The percent retention of AA in postdigestion samples was 22.68–51.39 (DG) and 15.67–44.0 (WG). Free radical scavenging activity indicated a different pattern, in which WG exhibited higher AA than DG and, among cooking methods, PC grains had higher activity. A reducing‐power assay showed similar results: DG had lower and PC samples had higher AA. Postdigestion AA of WG was higher for cooked than raw samples, although DG showed the opposite trend. In all cases, samples fortified with iron showed less AA because of prooxidant action of iron. In all assays, postdigestion samples had less activity than predigested extracts. In conclusion, germinated grains showed high AA, influenced by the presence of minerals, dehulling process, and cooking.     

水稻动态及静态谷层气流阻力的试验研究

应用二次Ｄ—饱和最优实验设计的方法,探讨了水稻在流动过程中顺、逆流通风的谷层气流阻力与风速、谷层厚度、粮食流动速度的关系,通过回归分析建立了动态谷层气流阻力的数学模型,对动、静态谷层气流阻力进行了对比分析,对水分的影响作了单因素试验分析,通过算术平均求出了理论公式（ΔＨ＝ａＬ_ｇｗ＋ｂＬ_ｇｗＶ^２）的动态计算系数ａ和ｂ。     

AP—Animal Production Technology: Predicting Sensor Placement Targets on Pigs using Image Analysis

This work forms part of a longer-term project aimed at developing a robot to bring a sensor into contact with an animal. The example application is to place an ultrasonic sensor onto the back of a pig as it uses a feeding stall. This paper presents the accuracy required in placing the sensor, and the accuracy of target location achieved using a linear function of landmark points on the pig outline, located by image analysis.The P2 standard position is close to a local minimum in fat thickness. When the target is chosen to be 25 mm ahead of the last rib and 50 mm from the mid-line of the pig, then a positional error of ±10 mm laterally and ±25 mm longitudinally will give a backfat measurement within 5% of the minimum.A linear model predicting the target position from six points on the outline was trained on 7549 images and tested on 2978 images. On the test data the root means square (r.m.s.) errors in the X and Y directions were 16 and 38 mm, respectively. A linear model with separate offset terms in X and Y coordinates for each sequence gave r.m.s. errors of 6 and 8 mm. However, this requires the offset value to be calculated for each sequence. An active system is proposed where multiple measurements from each pig will be used to improve the backfat estimate to within 5% of the minimum value.     

模拟酸雨对水稻、玉米和绿豆萌发及生长影响

通过模拟试验研究酸雨对水稻,玉米和绿豆的萌发及生长的影响,结果表明,ｐＨ２．０的模拟本雨明显降低作物的发芽率,伤害植物叶片,造成叶片细胞膜透性增加,使叶绿素含量,通过氧化氢酶和脱氢酶活性降低,ｐＨ３．０以上模拟酸雨短期内对作物无明显影响。     

丁香-鱼腥草-普鲁兰多糖复合涂膜对沙糖橘采后诱导抗性保鲜研究

为开发新型安全的植物源沙糖橘保鲜剂,本研究以沙糖橘为研究对象,探讨丁香、肉桂、鱼腥草和广藿香对沙糖橘的防腐保鲜效果,并以普鲁兰多糖为成膜剂,通过单因素和响应面试验筛选出最佳复合涂膜保鲜剂。结果表明,0.20 mg·mL^-1丁香水提液+0.10 mg·mL^-1鱼腥草水溶液+1.50%普鲁兰多糖复合涂膜保鲜剂处理组对沙糖橘的保鲜效果最佳。与空白对照组CK1和蒸馏水处理组CK2相比,在温度28℃、相对湿度75%、贮藏时间10 d的条件下,复合涂膜保鲜剂组处理的沙糖橘失重率分别降低了10.89、9.04个百分点,腐烂率分别降低了15、30个百分点,呼吸强度分别降低了42.97%、36.62%,可溶性固形物含量分别提高了2.70、3.51个百分点,V_C含量分别提高了57.72%、23.29%,可滴定酸含量分别提高了0.15、0.16个百分点。同时,复合涂膜保鲜剂处理组能诱导沙糖橘中过氧化物酶(POD)和多酚氧化酶(PPO)防御相关酶的活性,显著减少丙二醛含量的积累,从而提高其自身抗病性。复合涂膜保鲜剂组和0.225 g·L^-1咪鲜胺阳性对照组的保鲜效果无显著差异。本研究为开发新型安全的植物源沙糖橘保鲜剂提供了理论支持。     

硫化氢参与植物抗逆境胁迫研究进展及其在果蔬保鲜中的应用

低浓度的H₂S作为一种气体信号分子,在植物抗逆境胁迫中发挥着重要作用,能够缓解干旱、重金属等逆境胁迫带来的氧化损伤,激活采后果蔬抗氧化系统,调节活性氧(ROS)代谢平衡,对采后果蔬具有较好的保鲜效果。本文通过对H₂S参与植物抗逆境胁迫响应,H₂S与其他信号分子相互作用,以及H₂S在果蔬采后保鲜中的应用等方面进行综述,旨在为H₂S的深入研究提供参考依据。     

Small‐Scale Induction of Postharvest Yellowing of Rice Endosperm

Rice endosperm often develop a yellow discoloration during commercial storage in conditions of high temperature and moisture, thereby reducing the value of the grain. This postharvest yellowing (PHY) appears to be coincidental with fungal presence. To study the yellowing process in a controlled manner, we developed a technique to induce PHY on a small, laboratory scale. Milled rice kernels were rinsed with water and incubated in clear test tubes or microfuge tubes at 65–80°C. This allowed direct observation of the color change and measurement using a colorimeter. Every rice cultivar tested (long and medium grain japonicas and indicas) showed some level of PHY, which increased with temperature yielding a maximum color change at 79°C. Most color change occurred within one day. The moisture parameters required for yellowing to occur were measured. Using sterilization and culture techniques, we found no indications of direct fungal involvement in the yellowing process.     

Suitability of Lime,Green Leaf,and Farm Yard Manure and Inorganic Fertilizers for Sustaining Green Gram Yield and Rainwater Use Efficiency Under Moist Sub-Humid Alfisols in India

Field experiments were conducted to assess the effect of nutrients management practices on yield and rainwater use efficiency of green gram (Vigna radiata), and soil fertility under moist sub-humid Alfisols at Phulbani, India, during 2005–2008. Ten treatment combinations of lime @ 10% and 20% of lime requirement (LR) @ 8.3 t ha^?1, farmyard manure (FYM) @ 5 t ha^?1, green leaf manure @ 5 t ha^?1, and nitrogen, phosphorus, and potassium (N–P–K) (20–40–20 kg ha^?1) were tested. The analysis of variance indicated that treatments differed significantly from each other in influencing yield and rainwater use efficiency. Application of lime @ 20% LR + FYM @ 5 t/ha + 40 kg P + 20 kg K ha^?1 was superior with maximum mean yield of 531 kg ha^?1, while lime @ 10% LR + FYM @ 5 t ha^?1 + 40 kg P + 20 kg K ha^?1 was the second best with 405 kg ha^?1 and maintained maximum soil fertility of nutrients. The superior treatment gave maximum sustainability yield index of 67.5%, rainwater use efficiency of 0.49 kg ha^?1 mm^?1, improved soil pH, electrical conductivity, and soil nutrients over years.