多因素对开心果碰撞声特征的影响

设计了开心果碰撞声分拣试验装置,以开闭口果碰撞声的综合对数衰减率之差为判断依据,分析对比了传声器位置、开心果下落高度及碰撞块倾斜角度对碰撞声特征的影响。研究结果表明:在两种条件下,1传声器与碰撞面成45°,距离碰撞点10 cm左右时;2保持传声器在上述条件下的位置不变,开心果下落高度为70~100 cm、碰撞块倾斜角度为30°时,所采集到的声信号特征具有更好的分拣可靠性,使得开心果分拣设备的分拣准确率从70%提高至100%。     

碰撞位姿对开心果碰撞声离散性的影响

为了研究碰撞位姿对开心果碰撞声离散性的影响,在除碰撞位姿不作控制、其余条件均相同的情况下,分别对单个开闭口开心果进行100次重复碰撞试验,对两组碰撞声信号的频谱离散性和统计参数的离散性进行分析研究。频谱的离散性以样本信号频谱向量与其平均向量间的夹角均值和夹角变异系数作为度量;统计参数的离散性采用信号的能量、熵、过零率等参量,以其变异系数作为度量。试验结果显示:1单颗开口开心果重复碰撞声信号的频谱向量与其平均向量间夹角均值为30.94°,夹角变异系数为16.56%;能量、熵、过零率参数的变异系数分别为38.33%,2.30%,20.00%,均值分别为11.20,4.39,63.43;2单颗闭口开心果重复碰撞声信号的频谱向量与其平均向量间夹角均值为20.52°,夹角变异系数为25.11%;能量、熵、过零率参数的变异系数分别为18.36%,2.27%,13.08%,均值分别为6.08,4.28,62.94。结果表明:1不作控制的碰撞位姿对单颗开闭口开心果重复碰撞产生的声信号均有影响,会发生离散;2在由碰撞位姿导致的碰撞声的离散程度上,开口离散程度比闭口的高;3除碰撞位姿不作控制、其余试验条件均相同的情况下,虽然单颗开闭口开心果碰撞声的频谱和统计参数都会发生离散,但各参数均在其均值附近有限的范围内变动,所以,通过提取均值差异大且变异系数小的特征参数可以实现开口果和闭口果的有效分类。     

换热管弹性结构振动传递函数的建立

为了解决换热管振动的建模问题,提出了一种基于有限元分析的弹性振动传递函数建模方法。首先建立能准确反映换热管动力学特性的有限元模型,然后根据输入参数和辨识算法类型的不同,分别从时域和频域进行传递函数建模,其中时域辨识建模以PRBS信号的瞬态响应结果为辨识数据进行时域参数辨识,频域辨识建模以换热管的频响函数为辨识数据进行频域参数辨识。将有限元分析结果与时域和频域内传递函数计算结果进行对比,发现误差较小。该方法具有可行性和有效性。     

“不漂白·自然开”的万多福开心果上市

为了让中国消费者最便捷地享用到优质的加州开心果，全球最大的开心果种植加工商——美国派拉蒙农场近日将“万多福”品牌开心果带到了中国市场。“万多福”开心果果粒大，口味香，100％自然开口，绝不含其他坚果杂质，加工过程中也绝不添加油脂。     

基于撞击声分析的榛壳开口判别

撞击声分析是新型的坚果品级检测方法。为了研究开、闭口榛果的撞击声特性,通过不同的数据处理方法提取声信号的梯度累积特征、线性频谱特征和梅尔倒谱系数(MFCC)特征参数。研究结果显示:撞击声信号的累积梯度特征参数计算方便,阈值判断简单易行,识别精度可达80%左右;撞击声信号的线性频谱特征明显,闭口榛果撞击声能量集中在5~8kHz频段内,开口榛果撞击声能量趋于全频段内分散,较难寻找固定的频率特征参数;开闭、口榛果的辨识不能直接采用撞击声信号的MFCC特征参数,需要引入特定统计模型或应用人工神经网络,对特征参数进行训练,进而实现开闭、口榛果的模型识别。     

高品质开心果为健康加分

开心果、榛子、胡桃以及杏仁是全球最受欢迎的4种坚果食品。和其他3种坚果相比,开心果因其营养丰富、味道可口及吃法多样而倍受消费者欢迎。愉悦的名字美丽的传说在开心果的老家——中东地区,相传情人们常在开心果树下约会,在洒满月光的夜晚聆听开心果开裂的“噼啪”声,以期白头偕老。开心果香美的味道令当时的统治者——示巴女王钟爱不已,她下令在她统治的领土上所出产的开心果都只归她本人及王室成员享用。因而,这种“皇家”坚果至19世纪80年代才引进美国,消费者主要是具有中东血统的富人。大约50年之后,开心果才成为一种大众化的休闲食品…     

鸡蛋裂纹损伤检测的声振分析方法研究

敲击声信号法是鸡蛋裂纹检测方法之一,声信号检测法简便易行,但易受环境声干扰,精度和可靠性较差。在敲击声信号检测的基础上,增加了蛋壳振动信号检测分析。结果表明,声信号检测法中的声辐射能量源于鸡蛋壳体振动产生的结构辐射声,受蛋体自身阻尼特性及空气传播影响,其能量辐射有限,其检测结果需根据多次测试的能量总和进行判断;与声信号测试法相比,结构振动信号测试可直接获得鸡蛋壳体的振动能量,单次测量结果即可完成鸡蛋损伤的准确检测,1 500~3 000 Hz频段的频谱能量差异可以准确区分裂纹蛋和完整蛋。     

山核桃微波干燥动力学模型研究

针对山核桃坚果热风干燥效率低、能耗大、品质差等问题,采用单因素实验法,研究微波功率和装载量对山核桃坚果微波干燥特性的影响。根据微波干燥过程中山核桃坚果水分变化规律,探讨了不同微波功率、装载量下山核桃坚果干基含水率和失水速率随时间变化的规律,并建立山核桃坚果微波干燥动力学模型。实验结果表明:与装载量相比,微波功率对山核桃坚果干燥速率的影响大;山核桃坚果微波干燥过程分为加速干燥阶段和降速干燥阶段。通过分析,山核桃坚果微波干燥的动力学模型满足Page方程,根据干燥实验数据应用Matlab软件对干燥模型进行回归拟合求解,其模型系数在0.99以上。     

坚果及种仁食品对人体健康的影响

坚果是被子植物不裂干果的一个类型,指果壁硬或韧,通常含有一枚种子。种仁常称果仁,包括通常不列为坚果作物的种仁,如花生、瓜子。人们经常食用的坚果有榛子、核桃、大杏仁、开心果和夏威夷果,种仁有葵花子和西瓜子等。榛子、核桃、花生、瓜子和松子仁在我国有广泛来源,虽然大杏仁、开心果和夏威夷果主要产地是美国,但我国的新疆地区大杏仁、开心果也有大面积种植,在海南省和广西省也生产夏威夷果。现代研究表明:坚果、果仁食品除了具有特殊的风味、口感外,还具有相当高的营养价值和保健作用。一、坚果、种仁中脂肪及脂肪酸含量不同的坚果、…     

坚果类过敏原的分离及免疫印迹分析

本文采用传统的丙酮、乙醚溶剂去脂方法,选用不同品种和不同种类的坚果食品对其进行过敏蛋白的初步分离,应用BCA蛋白试剂盒测定各蛋白浓度,通过SDS-PAGE电泳分离坚果过敏蛋白各组份,采用免疫印迹(Western-blotting)方法鉴定坚果蛋白的过敏性。结果表明,各坚果蛋白提取浓度为白芝麻:14 mg/mL,黑芝麻:4 mg/mL,核桃:8 mg/mL,腰果:28 mg/mL,开心果:21 mg/mL。SDS-PAGE电泳显示15 ku是白芝麻的主要蛋白,34 ku是黑芝麻的主要蛋白,19和37 ku是腰果的主要蛋白,13 ku是核桃的主要蛋白,13和21 ku是开心果的主要蛋白。Western-Blotting显示对过敏患者的阳性混合血清均有过敏反应,坚果过敏具有同源性,白芝麻与黑芝麻的主要过敏原分子量均在22 ku,腰果的主要过敏原分子量在20 ku,核桃的主要过敏原分子量在54 ku,开心果的主要过敏原分子量在23 ku。     

Development of Pistachio (Pistacia vera L.) Spread

Pistachio nut (Pistacia vera L.) is one of the most delicious and nutritious nuts in the world. Pistachio spreads were developed using pistachio paste as the main component, icing sugar, soy protein isolate (SPI), and red palm oil (RPO), at different ratios. The highest mean scores of all the sensory attributes were depicted by spreads that were made without addition of SPI. It was found that the work of shear was 0 to 11.0 kg s for an acceptable spread. Sensory spreadability, overall texture, spreadability, and overall acceptability were negatively correlated (R > 0.83) with the work of shear of spreads. The findings indicated that the presence of RPO had a direct effect on the viscoelastic behavior of the pistachio spreads. The a values, which are related to the green color of the pistachio product ranged from 1.7 to 3.9 for spread without addition of RPO, and 4.0 to 5.3 in the presence of RPO. Practical Application The development of pistachio spread would potentially increase the food uses of pistachio and introduce consumers with a healthier snack food.     

Aflatoxin Removal from Pistachio Nuts by Natural Natrolite

ABSTRACT: Natrolite was used to explore a physical and safe method to decontaminate aflatoxin-containing pistachio lots. Pistachio nuts with low, medium, and high levels of aflatoxin were subjected to a washing process with a slurry of 5% natrolite. Using thin-layer chromatography and scanning, the aflatoxin contents of the samples were measured. Aflatoxins B₁ and B₂ were found in pistachio nuts. The majority of total aflatoxins was aflatoxin B₁ Natrolite treatment resulted in a 38% to 100% reduction in aflatoxin B₁, depending on the initial aflatoxin level. Although natrolite was demonstrated to be an effective candidate to reduce aflatoxin B₁, its efficacy against aflatoxin B₂ was limited.     

Pistachio nut allergy: An updated overview

Pistachio nut (Pistacia vera) is highly appreciated for its organoleptic characteristics and potential health benefits. However, this tree nut is also responsible for triggering moderate to severe IgE-mediated reactions in allergic individuals. Currently, pistachio nut allergy has gained some special attention, mainly due to its intrinsic relation with cashew nut allergy. Like for other nuts, the prevalence of pistachio nut allergy seems to be increasing at a global scale. Until now, there are five allergenic proteins officially listed for pistachio nut (Pis v 1, Pis v 2, Pis v 3, Pis v 4 and Pis v 5). Relevant data on their biochemical classification has become available, enabling establishing a correlation with the respective clinical symptoms. The establishment of an effective allergen risk assessment is a key issue for the food industry, policy makers and regulatory agencies. Thus, the availability of fast, specific and sensitive methods to detect trace amounts of allergens in processed foods is crucial. In the specific case of pistachio nut, there are some protein- and DNA-based methods for its detection/quantification in foods, which can aid to verify label information. Accordingly, all relevant research advances on this topic were summarised, updated and critically discussed in this review.     

Effects of Packaging Materials,Modified Atmospheric Conditions,and Storage Temperature on Physicochemical Properties of Roasted Pistachio Nut

Pistachio is one of the most important non-oil export items for Iran and also has the ability to adapt itself to adverse conditions including salinity, moisture stress, soil, and low water irrigation. It is one of the economical crops of desertic and dry areas and is recommended for such places. In this research, the effect of different packaging materials including five layers of compound film, modified polypropylene and metallized plastic, and packaging atmosphere on the quality of roasted pistachio nut were investigated. Atmospheric conditions were N₂/CO₂, vacuum, and ambient air at temperatures of 20 °C and 40 °C. Samples were tested in defined time intervals and then data were statistically analyzed. Results showed that packaging pistachio nut in metallized film and five-layer films with gases N₂/CO₂ and vacuum conditions kept the quality of pistachio better and lengthened shelf-life. A temperature of 40 °C compared to 20 C was a favorable condition for pistachio quality.     

电子自旋共振波谱法对干果类辐照食品的鉴定

研究电子自旋共振波谱法对干果类辐照食品的鉴定。分析开心果、核桃、桂圆的电子自旋共振波谱特征和样品干燥温度对信号强度的影响。结果表明：电子自旋共振特征峰信号强度与吸收剂量呈正相关,检测限为0.5kGy;进一步干燥时,开心果和核桃的最佳温度为40℃,桂圆的最佳温度为55℃;电子自旋共振特征峰的信号强度受微波功率影响,检测开心果、核桃、桂圆最佳的微波功率依次为0.59、0.37、0.24mW。通过电子自旋共振特征峰可判定干果是否经过辐照处理。     

Impact of Microclimate on Fatty Acids and Volatile Terpenes in “Kerman” and “Golden Hills” Pistachio (Pistacia vera) Kernels

Pistachio is an economically important nut crop in California. Since temperature variations among geographical locations can influence biochemical processes during fruit development, it is of great relevance to understand the impact of growing area over the components that define the nutritional and sensory characteristics of pistachio nuts. Changes in moisture, fat content, fatty acid composition and volatile terpenes were studied during kernel development for “Kerman” and “Golden Hills” varieties in two different California Central Valley microclimates, Lost Hills and Parlier. Moisture content decreased from July to September for both cultivars at both locations. Kerman had a higher moisture content at both locations compared with Golden Hills. Harvest time affected fat content only for Kerman, where the values increased drastically from 21‐July to 4‐Aug, then remained constant. Golden Hills’ fat content remained constant during the period of the study. The main fatty acid in pistachio oil is oleic acid (46% to 59%), followed by linoleic acid (26% to 36%) and palmitic acid (11% to 16%). C16:0, C16:1, C18:2, and C18:3 decreased with harvest time, while C18:1 increased. α‐Pinene was the most concentrated volatile among the cultivars and locations. It decreased with harvest time for both cultivars at both locations, ranging from 105 to 2464 mg/kg. At harvest, Golden Hills and Kerman at Parlier both had higher concentrations of α‐pinene than the two cultivars at Lost Hills. Our results demonstrate that microclimate affects biosynthesis of fatty acids and terpenes in pistachio kernels, the main compounds responsible for pistachio nutritional and sensory characteristics.     

Effect of gamma irradiation on the physico‐chemical and sensory properties of raw shelled peanuts (Arachis hypogaea L.) and pistachio nuts (Pistacia vera L.)

Backround The present study evaluated the quality of raw peanuts and pistachio nuts as a function of irradiation dose in order to determine dose levels causing minimal undesirable changes to these products. Physico‐chemical (colour, peroxide value, hexanal content, fatty acid composition, volatile compounds) and sensory (colour, texture, odour, taste) properties of raw peanuts and pistachio nuts were determined after irradiation at doses up to 7 kGy. Results Results showed an eight‐ and seven‐fold increase in peroxide value and a twelve and five‐fold increase in hexanal content after irradiation at a dose of 7 kGy for peanuts and pistachio nuts, respectively. An increase was also observed in saturated fatty acids (20.51–28.28% and 15.24–24.87%) with a parallel decrease in unsaturated fatty acids (79.49–71.72% and 84.76–75.13%) for peanuts and pistachio nuts, respectively. Likewise, volatile compounds such as aldehydes, alkanes, ketones and alcohols comprising secondary oxidation products of peanut and pistachio nut lipids increased after irradiation. Pistachio nut colour parameter a* and to a lesser extent parameters, L* and b* decreased after irradiation leading to a slight but noticeable darkening in product colour while colour parameter L*, b* and a* of raw peanut remained unchanged by irradiation up to 7 kGy. Conclusion Based on sensory evaluation, peanuts and pistachio nuts become unacceptable for consumption when irradiated at doses higher than 3 kGy. Copyright © 2009 Society of Chemical Industry     

基于虚拟仪器的精密球研磨加工的振动信号检测

振动信号是反映精密球体研磨状态的重要途径。利用加速度计传感器、数据采集卡和LabVIEW,设计了一套基于虚拟仪器的振动信号检测设备,对精密球在研磨加工过程中的振动信号进行了测试,从时域、频域等多个角度进行了分析论证。分析表明：精密球体研磨加工的振动信号能有效地监控整个研磨过程,能实时地反映球体研磨的状态和精度。图9参10     

Effect of chronic consumption of pistachios (Pistacia vera L.) on glucose metabolism in pre-diabetics and type 2 diabetics: A systematic review

Pistachio is a nut with high polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), polyphenols and carotenoids content, and the synergism between these compounds appears to affect glucose metabolism. In this systematic review we analyzed studies in which the effect of chronic consumption of pistachio on markers of glucose metabolism was evaluated in pre-diabetic and type 2 diabetics. We used the PubMed, Scopus, Cochrane and Lilacs databases. The research terms used were pistachio, pre-diabetes, type 2 diabetes mellitus, insulin resistance, blood glucose, hyperglycemia and glycated hemoglobin (HbA1c). Four articles were selected, of which three tested the intake of 50 to 57 g of pistachio/day and one 20% of the daily caloric intake, for a period of 1 to 4 months. Studies reported a decrease in fasting blood glucose, insulinemia, HOMA-IR, and fructosamine, but no change in HbA1c. Lower concentrations of miR-192 and miR-375 were also found, which correlated positively with HOMA-IR. The synergism between PUFA, MUFA, polyphenols and carotenoids present in pistachios can modulate specific miRNA, increasing insulin sensitivity through the PI3K-AKT signaling pathway. This modulation can be used as a tool to monitor the response to interventions, favoring the prevention and treatment of complications related to diabetes.