MEASUREMENT OR PEA,TENDERNESS II: A Review of Methods*

Abstract. Different methods used to measure pea tenderness are reviewed. Objective estimation of crop maturity, pea tenderness and quality has concerned researchers for many years. Chemical and mechanical methods have been used, and several instruments developed. There is a high degree of correlation between methods which also appear to agree with sensory analysis. For grading peas to establish the price paid to the grower, accuracy and economy under commercial conditions is of prime importance. Some methods are unsuitable on this basis, and presently used instruments and the manner in which they are operated require improvement.     

烤烟专业化分级散烟收购模式探讨

为适应现代烟草农业飞速发展需要,对传统把烟收购模式进行创新探索,以寻求适合产业进步的新型收购模式。通过散烟收购与传统把烟收购模式对比实践表明,与传统把烟收购相比,烘烤工场专业化分级散烟收购模式在减少烟农用工、节约成本、提高烟叶收购质量、增加烟农售烟收益方面效果明显;烟叶收购点散烟收购模式效果稍差,但优于传统把烟收购模式。综合分析,以烘烤工场收购模式总体效果最佳。     

DIFFERENTIATION OF PERFECTION, ALSWEET AND ALASKA VARIETIES BY TOTAL STARCH AND AMYLOSE CONTENT

The USDA grading system assigns different quality attributes according to two types of peas, wrinkled and smooth skinned. Since crosses between these types exist which exhibit characteristics of both types, a method of identification between types is needed to apply the correct grading standards. Perfection, Alsweet and Alaska varieties were evaluated for percent starch and amylose content in starch within sieve size classification or tenderometer value grouping. Perfection peas are easily differentiated from Alsweet and Alaska peas of similar sieve size or tenderometer values by their high amylose content. Alsweet has the lowest percent amylose in starch; however, there exists an overlap in content between Alaska and Alsweet varieties making differentiation uncertain. Results indicated that differentiation was possible between Alaska and Alsweet within sieve size or tenderometer values on the basis of total starch content. The Alaska variety has a higher total starch content compared to the Alsweet variety.     

Content of low molecular weight carbohydrates in vining peas (Pisum sativum) related to harvest time,size and brine grade

Knowledge of how the content of low molecular weight carbohydrates (LMWC), including the raffinose family oligosaccharides (RFO; raffinose, stachyose and verbascose), changes in unripe peas (Pisum sativum) around harvest time, is today limited. An early and a late maturing cultivar of peas were harvested with 24 h of each other on seven different occasions, of which three were chosen for this study. The pea samples were divided into three groups by size and brine grading, and then analysed with regard to the content of low molecular weight carbohydrates. The content of raffinose and stachyose increased in all groups during a period of 5 days. Peas that sank (sinkers) in the brine grading test had a higher content of raffinose and stachyose and a lower content of sucrose than floating peas, indicating that sinkers have reached a greater degree of maturation. The content of verbascose remained the same or decreased during the study period. In conclusion, the date of harvesting green peas for freezing affects the contents of RFO.     

Detection of fungal infection in five different pulses using near-infrared hyperspectral imaging

The five major pulse crops grown in Canada are: chick peas, green peas, lentils, pinto beans and kidney beans. Potential causes of fungal infection in these pulses are Aspergillus flavus and Penicillium commune. Early stages of fungal infections in pulses are not detectable with human eyes and traditional microbial methods require significant time to detect fungal infection. Near-infrared (NIR) hyperspectral imaging system is an advanced technique widely being assessed for detection of insect infestation and fungal infection in cereal grains and oilseeds. The primary objective of this study was to assess the feasibility of the NIR hyperspectral imaging system to identify fungal infections in pulses. Hyperspectral images of healthy and fungal infected chick peas, green peas, lentils, pinto beans and kidney beans were acquired and features (six statistical and 10 histogram) were used to develop classification models to identify fungal infection caused by A. flavus and P. commune. Images of healthy and fungal-infected kernels were acquired at 2 week intervals (0, 2, 4, 6, 8 and 10 weeks from artificial inoculation). Six-way (healthy vs the five different stages of infection) and two-way (healthy vs every stage of infection) models were developed and classifications were done using linear discriminant analysis (LDA) and quadratic discriminant analysis (QDA) classifiers. The LDA classifier identified both types of fungal infections with 90–94% accuracy while using the six-way model, and with 98–100% accuracy when using the two-way models for all five types of pulses. The QDA classifier also showed promising results as it gave 85–90% accuracy for the six-way model and 96–100% accuracy for the two-way models. The two fungal species could not be differentiated by the hyperspectral imaging.     

热牵伸辊非接触式旋转温度变送器的设计

 热牵伸辊表面温度测量精确度直接影响到热牵伸辊温控系统的控制精度,为此设计了旋转温度变送器,以解决热牵伸辊在高速旋转和高电磁强度下的精确测温问题。设备采用感应耦合电能传输技术,为其旋转部件非接触供电,使用集成了数模转换器的C8051F单片机完成温度采集和处理,并利用红外技术解决旋转部件的数据传输和抗干扰问题。软件方面采用滑窗平均滤波算法抑制干扰,采用分段线性插值法提升测温准确性。在辊体转速高达8000 r/min情况下,非接触式供电和红外数据传输稳定,温度测量精度达到0.1 ℃,3个多月运行结果表明,设备的稳定性及测量精度均达到设计要求。     

MEASUREMENT OF PEA TENDERNESS: III. Field Comparison of Several Methods of Measurement*

Five objective techniques were compared with pea tenderometers to examine their performance under field operating conditions. The methods were a shear-compression cell of the Kramer Shear Press, a back extrusion cell, wire and plate extrusion cells and a recording grinder. Results from the different methods were highly correlated allowing the choice of a test cell for possible replacement of the pea tenderometer to be based on practical considerations. The method selected for further development was the wire extrusion cell because it was inexpensive and suitable for a quality control instrument, where the maximum force during testing is a convenient value to record.     

Amylose content as a difference between heat-sterilised smooth and wrinkled garden peas

A method of determining the amylose content in starch of heat-sterilised garden peas is described. By this method a number of smooth and wrinkled peas and garden peas of the type Cennia in different size grades were analysed. The amylose content of wrinkled peas showed values between 38.6 and 85.8%, of smooth peas between 19.9 and 43.4% and of Cennia between 10.8 and 25.6%. These values overlap, but, in the corresponding size grades, the amylose content of the wrinkled peas is much higher than that of the smooth peas and this in turn is much higher than that of Cennia. Given a known size grade, the amylose content can be used to identify heat-sterilised garden peas when a microscopical examination is inconclusive.     

The relationship between lipid oxidation and antioxidant content in postharvest vegetables

Abstract

Lipid oxidation is the quality limiting attribute in many vegetables that generates off‐flavors. Lipoxygenases, which catalyze the oxygenation of polyunsaturated fatty acids are key enzymes in this pathway and their presence is believed to be the chief reason for the need for blanching (i.e., inactivation of enzymes) enabling frozen storage. Off‐flavor production in legumes, such as garden peas, is a particular problem, due to high levels of this enzyme found in these seeds.

The lipid oxidation pathway is triggered in response to tissue wounding which occurs during mechanical harvesting of peas in the field. Bruised peas that are not blanched develop strong off‐flavors within a few hours.

A number of studies has shown that antioxidants are consumed during lipid oxidation. Vitamin C (ascorbate) is an antioxidant and also an important micronutrient in peas. It is possible that the level of vitamin C is affected by the progress of lipid oxidation in postharvest peas.     

Pectin Methyl Esterase Activity in Southern Peas (Vigna sinensis)

SUMMARY: Pectin methyl esterase (PME) activity was investigated in vitro in Southern peas (Vigna sinensis). Experiments were conducted to determine the effect of NaCl concentration, pH, temperature, maturity, frozen storage and rinsing the peas on PME activity.
The optimum salt level for maximum PME activity in the Purple Hull Pink Eye (PHPE) and Princess Ann (PA) varieties was ascertained to be 0.25 M. The pH optima were: PHPE, 8.5; and PA, 7.5 to 8. The remaining studies were made using peas of the PHPE variety which were harvested at 3 stages of maturity. Maximum enzymatic activity occurred at 50°–60°C. Partial inactivation occurred at 65°C. The mean Q₁₀ was 1.35 over the range of 30°–50°C.
PME activity was dependent upon the maturity of the peas. The most immature peas had an activity level about 2.5 times that found in the most mature peas. Peas subjected to frozen storage had a higher activity than the fresh peas; the increased activity was more pronounced in the more mature peas.
Rinsing the peas removed significant amounts of the enzyme. A greater proportion of PME was removed from the more immature peas than from the more mature ones. With the immature, frozen peas PME activity was reduced 22.7% by rinsing; whereas, in the fresh counterpart the reduction was 11.1%. The rinse water from frozen peas contained more PME activity than did rinse water from fresh peas. Also, the activity in rinse water from the most immature peas was about 2.7 times that from the most mature ones. Upon standing, PME activity in the slurries prepared from frozen peas continued to increase up to 3–4 hr.     

The antioxidant activity and composition of fresh, frozen, jarred and canned vegetables

Regular consumption of dietary antioxidants may reduce the risk of several serious diseases. As vegetables are a major source of antioxidants it is desirable to assess their antioxidant activity and compare different processing and preparation methods. The total antioxidant activity was determined in water- and lipid-soluble extracts from fresh, stored and frozen vegetables. The contribution of individual compounds to total antioxidant activity was estimated. In stored vegetables at ambient or chill temperatures antioxidant activity declined. Blanching and freezing of peas and spinach reduced water-soluble antioxidant activity by 30 and 50%, respectively, thereafter levels remained constant on storage at −20 °C. Samples of frozen peas and spinach purchased from retail outlets had substantially higher antioxidant activity than canned or jarred samples. In a comparison of cooking methods, microwave and boiling for short periods had a negligible effect on total antioxidant activity, but substantial losses occurred after prolonged boiling in water.     

Biological response of broiler chickens fed peas (Pisum sativum L.) expressing the bean (Phaseolus vulgaris L.) α‐amylase inhibitor transgene

The nutritive value of transgenic peas expressing an α‐amylase inhibitor (α‐Ai1) was evaluated with broiler chickens. The effects of feeding transgenic peas on the development of visceral organs associated with digestion and nutrient absorption were also examined. The chemical composition of the conventional and the transgenic peas used in this study were similar. In the two feeding trials, that were conducted normal and transgenic peas were incorporated into a maize–soybean diet at concentrations up to 500 g kg^?1. The diets were balanced to contain similar levels of apparent metabolisable energy (AME) and amino acids. In the first trial, the birds were fed the diets from 3 to 17 days post‐hatching and with levels of transgenic peas at 250 g kg^?1 or greater there was a significant reduction in body weight but an increase in feed intake resulting in deceased feed conversion efficiency. In the second trial, in which the birds were fed diets containing 300 g kg^?1 transgenic peas until 40 days of age, growth performance was significantly reduced. It was also demonstrated that the ileal starch digestibility coefficient (0.80 vs 0.42) was significantly reduced in the birds fed transgenic peas. Determination of AME and ileal digestibility of amino acids in 5‐week‐old broilers demonstrated a significant reduction in AME (12.12 vs 5.08 MJ kg^?1 DM) in the birds fed the transgenic peas. The AME value recorded for transgenic peas reflected the lower starch digestibility of this line. Ileal digestion of protein and amino acids was unaffected by treatment. Expression of α‐Ai1 in peas did not appear to affect bird health or the utilisation of dietary protein. However, the significant reduction in ileal digestion of starch in transgenic peas does reduce the utility of this feedstuff in monogastric diets where efficient energy utilisation is required. Copyright © 2006 Society of Chemical Industry     

基于机器视觉的咖啡生豆快速检测与分级研究

目的 为了实现咖啡生豆的快速无损等级评估,建立一种基于机器视觉的咖啡生豆快速检测分级方法。方法 本次研究提取咖啡生豆图像预处理后的形状和颜色共13种特征,首先通过特征分布图分析与主成分分析找到13类缺陷豆的显著特征,并确定其显著特征值范围来判定缺陷豆,然后对正常豆按粒度大小判断其等级,最后在MATLAB App Designer平台上设计了咖啡生豆快速检测与分级界面。结果 研究表明,利用机器视觉技术能很好地识别各个类别咖啡生豆,检测一级咖啡生豆准确率为94.77%、二级为93.2%、三级为95.85%,13类缺陷豆平均准确率为82.25%,咖啡生豆检测平均准确率达到91.52%,检测300g咖啡生豆总用时25.3156s。结论 提高了咖啡生豆分级的智能化水平,分级过程平稳且快速,为今后咖啡生豆在线检测分选提供了技术支持。     

Effects of including raw or extruded field peas (Pisum sativum L.) in diets fed to weanling pigs

BACKGROUND: There is limited information about the response to field peas fed to weanling pigs. Two experiments were therefore conducted to investigate effects of including increasing levels of field peas in weanling pig diets. RESULTS: In Experiment 1, a reduction (linear, P < 0.05) in average daily gain (551, 574, 541, 548, 512 and 533 g d^?1) was observed in response to increasing levels of raw field peas (0, 120, 240, 360, 480 and 600 g kg^?1) in diets fed from day 14 to 42 post weaning. In Experiment 2, the inclusion of raw field peas (0, 245 or 490 g kg^?1) in the diets reduced (linear, P < 0.05) feed intake from day 14 to 39 post weaning, but average daily gain and gain:feed were unaffected by the use of raw field peas. The response to extruded field peas was not different from that to raw field peas. CONCLUSION: Up to 360 g kg^?1 raw field peas may be included in nursery diets without negatively influencing pig growth performance provided that diets are balanced for indispensable amino acids. Results from this work do not support any advantage of extruding the field peas. Copyright © 2010 Society of Chemical Industry     

A new method of shelling green peas for processing

Summary. A commercial machine for shelling peas was developed after numerous tests of methods for removing peas from pods. the pods are preheated in steam and then fed to a shelling section by means of a vibratory conveyor which aligns them for end-on presentation to a pair of rubber-covered rollers. A standardized feed gap between the conveyor and the rollers separates shelled peas from unshelled pods. Pods which fail to be gripped by the roller pass to a second slightly modified shelling section.
Extensive tests showed that a greater yield of peas was obtained from the sheller operated on hand picked peas, than from conventional stationary or mobile viners operated on vines. Yield for the combination of a mechanical pea pod picker which would be necessary for commerical operations and the pea sheller was not determined. Peas from the sheller were virtually undamaged in contrast to vined peas and were consequently superior in flavour.
Storage of pods for periods of several days before shelling led to an increase in pea maturity but quality was otherwise unaffected. Ability to store pods permits greater flexibility in harvesting and processing operations and allows an extension of the growing area serving a factory. In addition use of the pea sheller eliminates the need for most of the cleaning equipment as shelled peas are clean. Shelled peas pass directly to the processing line without any delay to cause deterioration.     

PROTEIN QUALITY OF FAFFA,THE ETHIOPIAN INFANT FORMULA AS AFFECTED BY PULSE SUBSTITUTION1

Faffa, the commercially produced infant formula in Ethiopia, contains approximately 20% protein derived from wheat, soy flour, chick peas and skimmilk. The paper examines the effect of substituting the chick peas in Faffa with haricot beans. Protein efficiency ratio (PER) was drastically reduced due to the substitution. Pre-toasting the haricot beans improved the PER value of the Faffa to the level of that of chick peas Faffa. The essential amino acid patterns of the two preparations of Faffa were found to be similar and therefore could not explain the difference in PER. It was suspected that improvement of PER by heat treatment of the haricot bean Faffa was due to inactivation of the trypsin inhibitor. Analysis for trypsin inhibitor content confirmed that the lower PER value for Faffa prepared from untoasted Faffa is due to higher trypsin inhibitor content of haricot beans as compared to chick peas.     

Pea proteins: A review of chemistry,technology of production,and utilization

Abstract

Dry peas are an important protein source for people and for animals. This paper reviews various aspects of the protein in dry peas, including variations in protein content, biochemical characteristics of the major protein components, and amino acid composition. The existing technology for the production of concentrated sources of pea protein (i.e., concentrates and isolates) is described. Finally the utilization of dry peas, pea flours, pea protein concentrates, and pea protein isolates is discussed. That discussion includes studies of the nutritonal value of peas and of the functional properties of dry pea ingredients in model systems and in food products. Topics for future research to enhance utilization of dry peas form the conclusion of this paper.     

基于机器视觉的牡蛎分级设备设计

目的：提高牡蛎分级的精确性和全面性。方法：提出并设计了牡蛎自动化分级设备,确定了旋转滚筒与挡板传送带结合的牡蛎排队结构、质量检测和机器视觉检测相结合的分级方式,完成了牡蛎分级设备的整体结构设计。通过工业相机采集牡蛎图像,使用大津法二值化、高斯滤波处理、Canny算子边缘提取等方法提取牡蛎图像,通过机器视觉算法以长度和饱满度为标准对牡蛎进行分级,并进行机器视觉分级与人工分级对比试验。结果：该设备分级准确率为95.4％,图像检测速度约为0.647 s/幅。结论：机器视觉对牡蛎分级是有效的,可以较为准确地对牡蛎进行分级。     

Effect of processing and storage on protein and lipid composition of peas

Changes in protein and lipid contents of peas (P. sativum L.) at various stages of processing and storage at different temperatures over a six-month period were studied. Blanching had very little effect on protein or protein amino acids of peas while free amino acids were greatly affected. Immediately after bottling and canning peas, total protein differed little from that of blanched, unpackaged peas. However, free amino acids decreased much more than did protein amino acids. Storage of canned peas for six months at room temperature caused changes in some protein amino acids.Total lipids of fresh peas did not change after blanching, bottling or canning. After storage for six months, no changes were observed in the total lipids while there were increases in glycolipids and decreases in phosphatides.Increases in monogalactosyl diglycerides and decreases in digalactosyl diglycerides were also observed.