CHANGE OF FAT CONTENT AND FATTY ACID COMPOSITION OF TURKISH HAZELNUTS (CORYLUS AVELLANA L.) DURING STORAGE

Hazelnuts (Corylus avellana L.) were collected from three different cultivars (Tombul, Palaz and Kal?nkara) at the harvest season of 1996. The dried nuts were stored shelled and unshelled in polyethylene bags at 21C and 60–65% relative humidity for 12 months. During storage, the total fat content increased, the palmitic and oleic acid content of the oil increased, linoleic acid, ranged from 12.41 to 10.35%. No significant differences were found for other fatty acids during storage. The effect of storage of shelled and unshelled hazelnuts on the total fat content was significant.     

近红外光谱波段优化在东北松子蛋白质定量检测中的应用

为了探究一种快速、无损与简便的东北松子品质检测方法,近红外光谱技术被应用到东北松子蛋白质无损检测研究中。利用偏最小二乘法建立带壳松子和去壳松仁的蛋白质定量分析模型,采用求导、多元散射校正、变量标准化校正、矢量归一化预处理方法优化模型,利用反向间隔偏最小二乘法、无信息变量消除法选取特征波段,建立全波段和特征波段下的偏最小二乘蛋白质预测模型。结果表明,带壳松子光谱经矢量归一化预处理方法后构建的模型最优,松仁光谱经变量标准化校正预处理方法后构建的模型最优;波段筛选能够优化模型质量,其中反向间隔偏最小二乘法的筛选结果最优,其带壳松子和松仁蛋白质模型校正集相关系数分别为0.9056和0.9383,验证集均方根误差分别为0.6670和0.5761。由此可知,经过优化后,模型的预测性能得到了提高,为带壳松子和松仁的蛋白质在线检测提供了一定的参考价值。     

Quality Evaluation of Shelled and Unshelled Macadamia Nuts by Means of Near‐Infrared Spectroscopy (NIR)

The quality of shelled and unshelled macadamia nuts was assessed by means of Fourier transformed near‐infrared (FT‐NIR) spectroscopy. Shelled macadamia nuts were sorted as sound nuts; nuts infected by Ecdytolopha aurantiana and Leucopteara coffeella; and cracked nuts caused by germination. Unshelled nuts were sorted as intact nuts (<10% half nuts, 2014); half nuts (March, 2013; November, 2013); and crushed nuts (2014). Peroxide value (PV) and acidity index (AI) were determined according to AOAC. PCA‐LDA shelled macadamia nuts classification resulted in 93.2% accurate classification. PLS PV prediction model resulted in a square error of prediction (SEP) of 3.45 meq/kg, and a prediction coefficient determination value (R_p²) of 0.72. The AI PLS prediction model was better (SEP = 0.14%, R_p² = 0.80). Although adequate classification was possible (93.2%), shelled nuts must not contain live insects, therefore the classification accuracy was not satisfactory. FT‐NIR spectroscopy can be successfully used to predict PV and AI in unshelled macadamia nuts, though.     

电感耦合等离子体质谱法测定食品中硒元素的条件优化

目的优化电感耦合等离子体质谱法(inductively coupled plasma mass spectrometer, ICP-MS)测定食品中硒元素含量的条件,并对河北省食品中硒元素含量情况进行调查分析。方法选取8种不同基质的国家标准物质作为检测样品对实验条件进行优化,同时选择80Se作为检测目标,采用碰撞模式并加入内标和5%异丙醇的优化条件下对样品中硒元素含量进行检测。通过对比结果,分析河北省膳食样品中硒元素含量,对居民通过膳食补充硒元素给予指导。结果通过采用碰撞模式及内标添加法可以有效降低基质干扰,同时加入异丙醇可极大提高硒元素的信号强度;其在5.00~100.00μg/L范围内呈现良好的线性关系(r2=0.999),检出限为0.002mg/kg;坚果及籽类、豆类及豆制品和肉及肉制品含硒较高,坚果及籽类样品中鲍鱼果含量最高为1.472mg/kg,豆类及豆制品中黄豆含量最高为0.123mg/kg,肉及肉制品中鸭肉含量最高为0.169 mg/kg。结论在检测的6类食品中,坚果及籽类、豆类及豆制品和肉及肉制品中硒含量相对较高,缺硒人群可适量增加食用。     

INSECT PROBLEMS OF PECAN SHELLING PLANTS AND THEIR RELATION TO INSECTS AND INSECT PARTS IN PROCESSED PECANS

SUMMARY– Factory studies were conducted to determine the incidence of various types of insect contaminants in inshell and shelled pecans and their significance as related to processing methods. Pecans may become infested in the field with primary and/or secondary insect pests and in the shelling plant by storage insects. Analytical results showed raw stock sorting by air separation to be ineffective for removing insect-infested inshell nuts. Insects and their fragments are present in cracked infested nuts and are largely removed by subsequent air separation procedures. During processing , Curculio caryae larvae are concentrated in the midget and small pecan pieces. Hand sorting under UV light was shown to be superior to other procedures for removal of curculio larvae from the finished product. Finished shelled pecan products contained relatively few insect fragments.     

Toxicity of Selenium in Brazil Nuts to Rats

Nuts from Bertholletia excelsa, commonly known as Brazil nuts, were analyzed for selenium. Of 529 nuts from one commercial source, 6% were found to contain 100 ppm selenium or more. The mean value for all nuts was 29.6 ppm and the median value was 13.4 ppm. Hexane extracted high-selenium Brazil nut meal in a corn-based diet fed to rats produced toxicity similar to that obtained from seleniferous corn, selenomethionine or sodium selenite as assessed by weight gain, visually scored liver damage, and liver, kidney, and spleen weights. Selenium contents of liver, kidney, spleen, and blood were also determined. It is suggested that the selenium in Brazil nuts is as biologically potent as that from other sources.     

Size and Moisture Distribution Characteristics of Walnuts and Their Components

The objective of this study was to determine the size characteristics and moisture content (MC) distributions of individual walnuts and their components, including hulls, shells, and kernels under different harvest conditions. Measurements were carried out for three walnut varieties, Tulare, Howard, and Chandler cultivated in California, USA. The samples for each variety were collected from the harvester at the first and second harvest of nuts treated with and without ethephon. The nuts were sorted into two categories as with hulls and without hulls before conducting dimension and MC measurements. The results showed that there was a wide range of size distribution for nuts with and without hulls and a huge variability in moisture content among individual nuts at harvest. The average MC of nuts with hulls was much higher than that of nuts without hulls for all tested varieties. The nuts with hulls had an average moisture content of 32.99% compared to 13.86% for nuts without hulls. Also, the shell moisture content was much higher than kernel moisture content. On average, the differences in moisture content between shell and kernel was 11.56% for nuts with hulls and 6.45% for nuts without hulls. There was no significant deference in hull MC between the first and second harvest for the studied varieties. Based on the regression analysis, it was observed that strong relationships exist between the MC of shells and kernels. The obtained results provide information for designing and developing new handling and processing equipments, especially for increased drying capacity, reduced energy use, and obtaining high-quality walnut products.     

Brazil nuts and associated health benefits: A review

Epidemiological studies have shown an inverse relationship between nut intakes and chronic diseases such as cardiovascular diseases and cancers. The composition of lipids, minerals, and phytochemicals, and their associated health functions in Brazil nuts are critically reviewed. The nuts have high nutritive food value containing 60–70% oil and 17% protein. Brazil nuts contain abundant dietary antioxidants, especially selenium (Se). One single Brazil nut provides 160% of the US Recommended Daily Allowance (RDA) of selenium - perhaps the best source of Se from plant-based foods. Brazil nuts possess phenolics and flavonoids in both free and bound forms and are rich in tocopherol, phytosterols, and squalene. These compounds' possible beneficial effects are due to their antioxidant and antiproliferative activities, which are linked to a reduced risk for developing atherosclerosis and cancer.     

In a nutshell: prospects and challenges on coatings for edible kernels

Edible kernels have been popular food items since ancient times. Although in-shell nuts are naturally protected and relatively shelf stable, convenience demands require their commercialization in shelled form. However, whereas shelled kernels are more convenient, they are more exposed to oxygen, and thus more susceptible to oxidative rancidity and loss of crunchiness, which negatively affect the product acceptability. In this review, we discuss the role of edible coatings in extending stability of edible kernels, which is an opportunity to be better explored by the industry. The discussion also includes the role of antioxidants in the context of active coatings. Finally, future prospects and research challenges are addressed. © 2019 Society of Chemical Industry     

银杏汁的加工工艺及品质测定

银杏的果仁含淀粉62.4%、粗蛋白11.3%、粗脂肪2.6%、蔗糖5.2%,还含有钙、钾、磷、硒等矿物质、微量元素和多种维生素等生物活性物质。天然银杏汁既有利于人体对银杏营养成分的吸收,又降解了银杏的有毒成分银杏酸、银杏酚等物质,具有安全性。银杏汁在制作工艺、风味及稳定性等方面存在问题。通过对天然银杏汁在生产中的均质压力、稳定剂的选择、风味的调配等进行了对比实验,得出最佳配比和工艺参数。银杏汁的配比为银杏每瓶6.00 g,含糖量为3.05 g/100 mL,含酸量为0.5 g/L,0.15%海藻酸钠,0.1%CMC-Na(羧甲基纤维素钠),均质压力为40 MPa,品质最好。     

Effect of Moisture Content,Nut Size and Hot-Oil Roasting Time on the Whole Kernel “Out-Turn” of Cashew Nuts (Anacardium occidentale) During Shelling

The effect of moisture content (MC), nut size and roasting time (RT) on the whole kernel out-turn (WKO) of cashew nuts during shelling was investigated in this study. Cashew nuts were graded into three sizes: small (18 – 22 mm), medium (23 – 25 mm) and large nuts (26 – 35 mm). About 3 kg of nuts from each grade was conditioned with water at 25°C to five moisture levels of 8.34, 11.80, 12.57, 15.40 and 16.84% (wb). The nuts were subjected to roasting in hot cashew nut shell liquid at a temperature range between 180 and 190°C for 0.75, 1.00, 1.25, and 1.50 min. The nuts were then shelled using a hand-operated shelling machine. The results showed that pre-shelling treatment of cashew nuts enhanced WKO. The single effect of MC, roasting time (RT) or nut size distribution is not enough for estimating WKO; it is rather by an interaction of these parameters. The average WKO of raw nuts was characteristically below 50% at all combinations of MC and RT. Pre-treatment by roasting was found to improve WKO considerably. The highest values were 96.96, 99.63 and 100% for large, medium and small-sized nuts at MC*RT of 16.84%*1 min, 16.84%*1 min and 15.4%*1.5 min respectively. As RT and MC increased, WKO increased within the experimental range.     

Effect of harvest time and storage conditions on almond kernel oil and sugar composition

The effect of storage for 6 months at 5 °C (80% RH) versus 20 °C (60% RH) of shelled versus in‐shell almonds was studied on early versus late harvested nuts from ‘Ferragnes’ and ‘Texas’ trees. Kernel quality characteristics, oil composition and sugar composition were determined initially and after 6 months of storage. Early harvested almonds had similar kernel weight to but higher moisture content than late harvested almonds after 6 months of storage. Early harvested almonds also had similar oil quality (based on ultraviolet absorption coefficient measurements) and oil composition but lower sugar content and modified sugar composition compared with late harvested almonds. Storage of shelled almonds resulted in kernels with higher oil content, better oil quality, similar oil composition, similar sugar content and some modifications in sugar composition compared with in‐shell stored almonds. Finally, storage for 6 months at either 5 or 20 °C resulted in lower moisture content, higher oil content, similar oil quality and composition, similar sugar content and some modifications in sugar composition compared with freshly harvested almonds. Almonds stored at 5 °C retained higher kernel weight and moisture content than almonds stored at 20 °C. © 2003 Society of Chemical Industry     

Predominant mycobiota and aflatoxin content in Brazil nuts

The Brazil nut (Bertholletia excelsa) is an economically important product to the Brazilian Amazon. Currently, its marketing is being affected by the high incidence of aflatoxins (AF) produced by potentially aflatoxigenic fungi associated with its seeds. In this context, the purpose of this study was to determine which part of the nut contributes to contamination by aflatoxins and to identify the mycobiota in Brazil nut samples. Unshelled and shelled nuts were analyzed by measuring the total count of filamentous fungi (Aspergillus sections Flavi, Nigri and Circumdati) in sanitised and non-sanitised treatments. The isolates identified as Aspergillus section Flavi, the major producers of AF, were plated for determination of their aflatoxigenic potential. To perform the AF analysis, samples of Brazil nuts were treated separately. The AF from the shell and kernel were extracted by chloroform and analysed by the HPLC-FD system in isocratic mode. The Aspergillus section Flavi count was 21.67% lower. The production of AF by the isolated fungi was 30% for sanitised and 23.8% for non-sanitised samples. The concentrations obtained of AFB₁ and AFG₁ were higher than those of AFB₂ and AFG₂. The AFB₁ concentrations of shelled nuts and shell samples were 35.0 and 1.78 μg/kg, respectively. AFB₂ and AFG₂ were detected only in shelled nut samples. The HPLC-FD analysis presented limits of detection (LOD) and quantification (LOQ) of 0.2 and 0.4 μg/kg, respectively.     

Selenium content of feeds and effect of dietary selenium on hair and blood serum.

A selenium depletion diet (.025 ppm selenium) was fed to two male Holstein calves for its effect on concentrations of selenium in serum. By 90 days, selenium in serum was depressed from .022 ppm to .013 ppm, and one of two calves had died of "possible white muscle disease." Repletion was rapid in that a diet containing .200 ppm selenium increased selenium in serum to .028 ppm within 2 wk. Dietary .280 ppm selenium increased it to .051 ppm in 1 wk. Eleven cows and eleven calves showed averages of .030 ppm in serum (range of .013 to .051 ppm) fed a diet of corn silage (.039 ppm) and supplement (.090 ppm). A sampling of feedstuffs showed a wide range of selenium among feedstuffs (.023 for corn cobs to 2.663 ppm for dried egg albumin) and a wide range within one type feedstuff (shelled corn, .017 to .219 ppm).     

Predominant mycobiota and aflatoxin content in Brazil nuts

The Brazil nut (Bertholletia excelsa) is an economically important product to the Brazilian Amazon. Currently, its marketing is being affected by the high incidence of aflatoxins (AF) produced by potentially aflatoxigenic fungi associated with its seeds. In this context, the purpose of this study was to determine which part of the nut contributes to contamination by aflatoxins and to identify the mycobiota in Brazil nut samples. Unshelled and shelled nuts were analyzed by measuring the total count of filamentous fungi (Aspergillus sections Flavi, Nigri and Circumdati) in sanitised and non-sanitised treatments. The isolates identified as Aspergillus section Flavi, the major producers of AF, were plated for determination of their aflatoxigenic potential. To perform the AF analysis, samples of Brazil nuts were treated separately. The AF from the shell and kernel were extracted by chloroform and analysed by the HPLC-FD system in isocratic mode. The Aspergillus section Flavi count was 21.67% lower. The production of AF by the isolated fungi was 30% for sanitised and 23.8% for non-sanitised samples. The concentrations obtained of AFB₁ and AFG₁ were higher than those of AFB₂ and AFG₂. The AFB₁ concentrations of shelled nuts and shell samples were 35.0 and 1.78???g/kg, respectively. AFB₂ and AFG₂ were detected only in shelled nut samples. The HPLC-FD analysis presented limits of detection (LOD) and quantification (LOQ) of 0.2 and 0.4???g/kg, respectively.     

Aflatoxin production by Aspergillus flavus in Brazil nuts

Experiments were conducted to evaluate the effects of relative humidity (r.h.; 75%, 80%, 85%, 97%) and temperature (10, 13, 15, 25, 30 °C) on aflatoxin production in previously dried (3.5% moisture content; m.c.) Brazil nuts. Initially Aspergillus spp. were isolated from the surfaces of whole in-shell (WIS) Brazil nuts imported from Peru using A. flavus and A. parasiticus agar (AFPA). Isolates were subsequently screened for aflatoxin production using yeast extract sucrose medium. Total aflatoxin (B₁+B₂+G₁+G₂+M₁) was analyzed using an immunoassay technique while the presence of aflatoxin was confirmed using thin-layer chromatography. The surface of shelled half-nuts (simulating damaged or trimmed nuts), shelled whole (SW) nuts, and WIS nuts following a chlorine wash and water rinse, served as sites for inoculation (10 μl; 10⁵/ml) using an aflatoxigenic isolate. Maximum concentrations of total aflatoxin and B₁ were detected in nuts stored at 97% r.h. and at temperatures of 25–30 °C. Shelled half-nuts contained the highest total (6817 ng/g) and B₁ (4483 ng/g) aflatoxin. WIS nuts contained the least total and B₁ toxin with maximum concentrations of 93 and 49 ng/g, respectively. Aflatoxin was not detected (detection limit of 1.75 ng/g) in nuts maintained at either 10 °C (97% r.h.) or at 30 °C (75% r.h.) for up to 60 d. Maximal moisture contents (%) and water activity values (a_W) for nuts stored at these conditions were 4.50 and 0.78, and 9.14 and 0.92, respectively. Results of this study indicate that the limiting moisture content and a_W values required to control aflatoxin production () in SW and WIS stored at 30 °C for up to 60 d are 4.5, 0.68, 5.0, and 0.75, respectively. Overall, increasing the relative humidity and temperature during storage resulted in an increase in aflatoxin and these were shown to be the most significant variables influencing toxin production in Brazil nuts.     

坚果的主要生物活性成分及其保健作用

坚果作为高档零食,其营养价值和保健功能也越来越受到人们的关注?本论文综述了常见坚果(如澳洲坚果、核桃、榛子、杏仁、松子、板栗、山核桃、开心果,日本核桃、巴西坚果、花生等)中的酚类(原花青素、酚酸、黄酮、单宁、烷基酚、维生素E等)?酸类?甾醇类、色素(类胡萝卜素、叶绿素等)、硒、糖苷、功能性脂肪酸等营养物质和生物活性成分,并阐述了食用坚果与预防心血管疾病?延年益寿?预防糖尿病?控制体重等保健作用的关系?这对于进一步研究坚果与健康的关系、正确挑选与消费坚果均具有较好的指导意义。     

Predicted dietary intake of selenium by the general adult population in Belgium

The total selenium content of about 800 food products purchased in Belgium was determined and combined with food records to determine the nutritional selenium status of Belgian people. The largest selenium concentrations (>1?mg?kg^?1) were found in Brazil nuts and offal, of which the consumption is limited. Usually consumed food groups with the highest selenium concentrations were fish and shellfish (0.2–0.9?mg?kg^?1), eggs, poultry meat, cheese, mushrooms and pasta (approximately 0.2?mg?kg^?1). The mean dietary selenium intake was calculated to be 60?µg?day^?1, which is at the lower end but within the range recommended by the Superior Health Council in Belgium (60–70?µg?day^?1), and adequate according to the 55?µg?day^?1 recommended by the Scientific Committee on Food (SCF) of the European Commission. The major sources of selenium intake are meat and meat products (31%), fish and shellfish (20%), pasta and rice (12%), and bread and breakfast cereals (11%).     

Management and prevention of mycotoxins in peanuts

Contamination of peanuts with mycotoxins, particularly aflatoxins, is a worldwide problem that affects both food safety and agricultural economies. Most countries have adopted regulations that limit the quantity of aflatoxins in food and feed to 20 µg kg^-1 or less; however, environmental conditions in most of the world where peanuts are produced and stored often make it difficult or impossible to attain such low concentrations. In addition to aflatoxins, peanuts are often contaminated with cyclopiazonic acid (CPA). Both mycotoxins are produced by Aspergillus flavus, a ubiquitous fungus that can infect and grow in peanuts under both pre- and post-harvest conditions. Management of mycotoxin contamination in peanuts generally involves removal of high-risk components from shelled lots or the removal of individual, highly contaminated nuts. This is accomplished by various processes such as screening, kernel sizing, electronic colour sorting, hand sorting, and blanching followed by electronic colour sorting. Recently, biological control technology has been developed that prevents much of the contamination that might otherwise occur. Biocontrol is based on competitive exclusion whereby a dominant population of a non-toxigenic strain of A. flavus is established in the soil before peanuts are subjected to conditions favouring contamination. The applied strain competes with toxigenic strains for infection sites, resulting in significantly reduced concentrations of aflatoxins in peanuts. Monitoring of the first commercial use of the technology showed that aflatoxins were reduced by an average of 85% in farmers' stock peanuts and by as much as 98% in shelled, edible grade peanuts.     

Determination of aflatoxin risk components for in-shell Brazil nuts

A study was conducted on the risk from aflatoxins associated with the kernels and shells of Brazil nuts. Samples were collected from processing plants in Amazonia, Brazil. A total of 54 test samples (40 kg) were taken from 13 in-shell Brazil nut lots ready for market. Each in-shell sample was shelled and the kernels and shells were sorted in five fractions: good kernels, rotten kernels, good shells with kernel residue, good shells without kernel residue, and rotten shells, and analysed for aflatoxins. The kernel:shell ratio mass (w/w) was 50.2/49.8%. The Brazil nut shell was found to be contaminated with aflatoxin. Rotten nuts were found to be a high-risk fraction for aflatoxin in in-shell Brazil nut lots. Rotten nuts contributed only 4.2% of the sample mass (kg), but contributed 76.6% of the total aflatoxin mass (μg) in the in-shell test sample. The highest correlations were found between the aflatoxin concentration in in-shell Brazil nuts samples and the aflatoxin concentration in all defective fractions (R(2)=0.97). The aflatoxin mass of all defective fractions (R(2)=0.90) as well as that of the rotten nut (R(2)=0.88) were also strongly correlated with the aflatoxin concentration of the in-shell test samples. Process factors of 0.17, 0.16 and 0.24 were respectively calculated to estimate the aflatoxin concentration in the good kernels (edible) and good nuts by measuring the aflatoxin concentration in the in-shell test sample and in all kernels, respectively.