Modeling of rice hydration using finite elements

Great effort has been devoted towards developing models that describe cooking processes. A difficulty towards developing such models arises from the fact that during cooking, the physical properties and quite often sample geometry are time dependent. In this work a finite element model describing cooking of rice and water uptake using a Fickian diffusion model was developed, assuming axisymmetric conditions. Effective diffusivity was considered a function of moisture content. The numerical model compared favorably with experimental results. The value of the effective water diffusivity was estimated to be in the order of 7 × 10⁻¹⁰ m²/s, by minimizing the error between experimental and numerically predicted results.The effect of grain size on the cooking was also investigated using the model. Cooking time, i.e. the time to reach about 70% moisture content (wet basis), appeared to be a strong function of the initial size distribution.     

Enzyme-linked immunosorbent assay of 3-acetyldeoxynivalenol applied to rice

An enzyme-linked immunosorbent assay for the detection of 3-acetyldeoxynivalenol has been set up with an antiserum preparation raised against a bovine serum albumin—3-acetyldeoxynivalenol hemiglutarate conjugate. The assay is an indirect, double antibody immunoassay performed on microtitration plates, and is sensitive (with a limit of detection of 1 pg per well) and specific. The assay has been validated for application to rice with a sensitivity of 1 ng g^?1. Sample extraction is a simple solubilisation procedure. The immunoassay described has a number of advantages over conventional methods of analysis.     

Assessing drivers of maize storage losses in south west Benin using a fractional response model

An assessment of drivers of maize storage losses was undertaken in south west Benin applying the Fractional Response Model on information collected from 400 smallholder maize farmers. The mean loss of maize during the storage period reported by farmers was estimated at 10.25 percent of the total harvest. The average marginal effect obtained from the fitted Fractional Response Model revealed that storage technologies, farmers’ post-harvest attitudes, insect damage, weather conditions and infrastructures play a significant role in storage losses maize farmers experience in south west Benin. The findings revealed that farmers who used bags and plastic containers respectively reduced storage losses by 6.7 and 7.8 percentage points compared to farmers who used woven granary baskets. The results also indicated that applying ash, neem leaves, pepper or lemon increased the storage loss by 4.11 percentage points compared to storing without protectant. Drying after harvesting decreased the storage loss by 1.9 percentage point. In contrast, the storage loss increased by 5.1 percentage points for respondents who reported insects as predators of their stored maize, and by 2.1 percentage points when it rains at the time of maize harvest. A one-degree increase in temperature was associated with an increase in storage losses of 4.4 percentage points and farmers who live at less than 26.09 km to market reduced storage losses by 0.17 percentage point. Effective policies for a sustainable reduction of storage losses among maize farmers in the area should consider the need to raise awareness about the loss issue that represents the use of woven granary basket, ash, neem leaves, pepper and lemon as storage technologies. Farmers should be informed to avoid harvesting during times of rain, encouraged to properly dry their produce after harvesting and sustainable hermetic equipment robust against insect growth during storage should be promoted.     

Genetic parameters for tunisian holsteins using a test-day random regression model

Genetic parameters of milk, fat, and protein yields were estimated in the first 3 lactations for registered Tunisian Holsteins. Data included 140,187; 97,404; and 62,221 test-day production records collected on 22,538; 15,257; and 9,722 first-, second-, and third-parity cows, respectively. Records were of cows calving from 1992 to 2004 in 96 herds. (Co)variance components were estimated by Bayesian methods and a 3-trait-3-lactation random regression model. Gibbs sampling was used to obtain posterior distributions. The model included herd × test date, age × season of calving × stage of lactation [classes of 25 days in milk (DIM)], production sector × stage of lactation (classes of 5 DIM) as fixed effects, and random regression coefficients for additive genetic, permanent environmental, and herd-year of calving effects, which were defined as modified constant, linear, and quadratic Legendre coefficients. Heritability estimates for 305-d milk, fat and protein yields were moderate (0.12 to 0.18) and in the same range of parameters estimated in management systems with low to medium production levels. Heritabilities of test-day milk and protein yields for selected DIM were higher in the middle than at the beginning or the end of lactation. Inversely, heritabilities of fat yield were high at the peripheries of lactation. Genetic correlations among 305-d yield traits ranged from 0.50 to 0.86. The largest genetic correlation was observed between the first and second lactation, potentially due to the limited expression of genetic potential of superior cows in later lactations. Results suggested a lack of adaptation under the local management and climatic conditions. Results should be useful to implement a BLUP evaluation for the Tunisian cow population; however, results also indicated that further research focused on data quality might be needed.     

Odour sampling system with modifiable parameters applied to fruit classification

The aroma emanating from fruits can indicate the maturity level and thus the quality and shelf life of the products. In this work it is presented an odour sampling system system (called also electronic nose), to classify the aroma of Diospyros kaki, whose working parameters can have variable configuration making the system flexible. The system can be appropriately reconfigured for each type of sampling. It is formed by a metal oxide semiconductor (MOS) commercial sensors matrix, which are individually controlled, being able to modify by software several parameters of their operating point. Working this way there is not a limited number of sensors but a very high number of virtual sensors. The system shows the ability to discriminate aroma of two Diospyros kaki cultivars. Moreover the instrument is capable to distinguish the fruits, inside the persimmon cultivar cluster, according to the ripe state after few days of storage.     

Genetic parameters for stillbirth in Danish Holstein cows using a Bayesian threshold model

The objective of this study was to make an inference about the direct and maternal genetic variation of stillbirth for first-calving Holstein cows and to estimate the effect of breed and heterosis for original Danish black and white and Holstein-Friesian. A Bayesian threshold model, which included correlated genetic effects of sires and maternal grandsires was used. Marginal posterior distributions of effects were obtained using Gibbs sampling. Point estimates were compared with results from a linear model using REML. Data with and without twins were analyzed and models with and without effects of breed and heterosis were fitted, but estimates of genetic parameters were almost identical. In all the analyses with threshold models, the marginal posterior mean (and standard deviation) was 0.10 (0.014) for the direct heritability, 0.13 (0.015) for the maternal heritability, and 0.05 (0.10) for the genetic correlation between direct and maternal effects. The stillbirth rate tended to increase with a higher proportion of Holstein-Friesian in the calf and in the dam, but no effects of breed and heterosis were significant. Joint sampling of all location parameters was found superior to univariate sampling in terms of much better mixing properties of the fixed effects. Based on the results showing genetic variation for stillbirth at first calving, both the direct and the maternal effect could be included in the breeding program.     

红曲粉应用于鸭脖的制作工艺优化研究

确定灭菌方法和保藏方法后,选取红曲粉添加量、添加时间、卤汁pH值三个因素作为考察对象,在单因素试验的基础上,利用Box-Benhnken中心组合设计和响应面分析法对鸭脖制作的工艺参数进行优化研究。结果表明:在红曲粉添加量为0.18%、添加时间为33.4min、卤汁pH值为6.0时,制作的鸭脖呈现的色泽最佳。     

Impact of heat-moisture treatment applied to brown rice flour on the quality and digestibility characteristics of Korean rice cake

Effect of heat-moisture treatment (HMT) of brown rice flour on the quality and digestibility of Korean rice cake (jeolpyeon) was investigated. Brown rice flour with 20% moisture content was heat-moisture treated at 100–110 °C for 1–2 h, and subsequently cooled to 4 °C for 1–2 h. The lightness of HMT rice cake decreased as HMT temperature and time increased, whereas redness and yellowness increased. The hardness, springiness, and cohesiveness of HMT rice cake were much lower than those of brown rice cake. HMT of rice cake caused an increase in the resistant starch content and a decrease in the rapidly digestible starch content. In sensory evaluation, hardness of HMT rice cake was substantially lower than that of rice cake made with untreated brown rice due to retardation of retrogradation. However, the overall acceptability of HMT rice cake was lower than that of white rice cake or brown rice cake.     

A comparative study of Indian rice starches using different modification model solutions

Starches extracted from rice flour from broken kernels of three rice cultivars (PUSA-44, PR-106 and PR-114) have been selected for modification studies due to their varied amylose content. Model solutions with different types and concentrations of modifying agents were prepared for comparative study of effect of amylose variation among the varieties and also individual and combined effect of modifying agents used. There was an increase in hot paste viscosity at 90 °C in modified starches whereas, cold paste viscosity decreased upon modification. A greater effect was observed with in dual modification of starches. The total set back was significantly lower in modified starches indicating the decreased retro-gradation of starch gels upon modification. The DSC results showed decreases in ΔH, T_o, T_p, and T_c, indicating that hydroxypropylation cross-linking and acetylation affect the structure of starches granules, requiring less heat for gelatinization. Pasting and thermal properties of PUSA-44 were significantly different from those of PR-106 and PR-114, probably due to relative higher amylose contents in the former. As observed in this study, bi-functional modifying agents can reduce the extent of cross-linking. Acetylation modified the morphology of the starch. However, hydroxypropylation cross-linking and dual modification retained the original structure with little modification.     

Genetic parameters derived from using a biological model of lactation on records of commercial dairy cows

The object of this study was to investigate the genetics of lactation curve parameters derived from a biological model of lactation and the relationships among them. This biological model fitted 2 logistic curves to mimic the initial increase in milk secretory cell numbers in early lactation and the progression of apoptosis in late lactation. Records from 82,255 Holstein-Friesian heifers from commercial dairy herds in the United Kingdom, recorded from 1994 to 2003, were analyzed. The heritabilities of 2 lactation curve parameters, maximum secretion potential and relative cell death rate, were 0.27 and 0.08 respectively. Maximum secretion potential was highly genetically correlated with peak yield (0.99), and relative cell death rate was highly correlated with persistency of lactation (0.84). Heritability values for the traits analyzed showed a characteristic pattern. Total milk yield traits, maximum secretion potential, and peak yield had similar and moderate heritabilities (∼0.3). Traits associated with late lactation had lower heritability values (∼0.1), whereas day of peak yield and early lactation traits had little genetic variation. The permanent environmental variance of the various traits ranged from 0.08 to 0.26 of the phenotypic variance. Parameters from the 2 logistic curves were not highly correlated, suggesting that selection programs could be devised to exploit genetic variation in both aspects of lactation independently.     

膨化大米辅料酿造啤酒中糖化工艺参数对啤酒酒精含量的影响

在100L规模上,通过五因素五水平二次旋转正交组合试验设计,探讨了膨化大米辅料酿造啤酒的外加酶糖化工艺参数对啤酒酒精含量的影响规律,得出最佳的糖化工艺参数。     

The structural and hydration properties of heat-treated rice studied at multiple length scales

The impact of heat-treatment on structure and hydration properties of rice was studied at different length scales (μm–nm). Heat-treatment introduced micro- and macro-pores within rice kernels (μCT) and, within intact cell walls, disintegrated starch granules were observed (SEM, CSLM). In native kernels starch predominantly occurred as crystalline A-type starch and, upon heat treatment, amorphous and V-type starch appeared (XRD, ¹³C CP MAS NMR). Plasticization of amorphous starch by water was more pronounced for heat-treated than for native kernels (¹³C SPE MAS NMR). Within native kernels, more effective spin diffusion between water and starch chains was present (WISE-Exchange), confirming the inter-helical nanoscale order of amylose helices. Upon heat-treatment, this inter-helical nanoscale order was lost, as well as microscale granular compartmentalisation (TD NMR). These findings explain why, upon heat-treatment, vapour sorption is lower and starch is more prone to gelatinization (DSC).     

Response surface methodology applied to the analysis of rice bran oil extraction process with ethanol

Vegetable oils can be extracted using ethanol as solvent. The main goal of this work was to evaluate the ethanol performance on the extraction process of rice bran oil. The influence of process variables, solvent hydration and temperature was evaluated using the response surface methodology, aiming to maximise the soluble substances and γ‐oryzanol transfer and minimise the free fatty acids extraction and the liquid content in the underflow solid. It can be noted that oil solubility in ethanol was highly affected by the water content. The free fatty acids extraction is improved by increasing the moisture content in the solvent. Regarding the γ‐oryzanol, it can be observed that its extraction is affected by temperature when low level of water is added to ethanol. On the other hand, the influence of temperature is minimised with high levels of water in the ethanol.     

红曲米粉应用于猪冷鲜肉的保鲜效果

采用不同添加量的红曲米粉(100g肉样中含有红曲米粉0,0.0625g,0.125g、0.25g、0.5g、1g)应用于冷鲜肉,随冷藏天数(0,1,2,3,4,5,7,9d)的延长,测其pH及高铁肌红蛋白的变化。对其感官指标和理化指标进行测定,根据结果评价红曲米粉应用于猪肉的保鲜作用。结果显示添加量为0.125g/100g肉样和0.25g/100g肉样的实验组,不仅感官评价、理化指标等较好,保鲜效果也比较优异,相对于空白组,可以有效地将保存期延长3～5d。     

蒸谷米浸泡工艺参数初探

通过研究浸泡温度、浸泡时间、浸泡压力对蒸谷米含水量的影响,采用正交试验优化蒸谷米浸泡工艺参数,经过中试试验修正的工艺参数为:浸泡温度55℃、浸泡压力400kPa、浸泡4 h.