Influence of domestic processing and storage on flavonol contents in berries

Effects of domestic processing and storage on the flavonols quercetin, myricetin, and kaempferol in five berries were studied using an optimized RP-HPLC method with UV and diode array detection after an acid hydrolysis of the corresponding glycosides. In fresh berries, the total content of flavonols was highest in lingonberry (169 mg/kg) and black currant (157 mg/kg), intermediate in bilberry (41 mg/kg) and strawberry (17 mg/kg), and lowest in red raspberry (9.5 mg/kg). Cooking strawberries with sugar to make jam resulted in minor losses (quercetin 15%, kaempferol 18%). During cooking of bilberries with water and sugar to make soup, 40% of quercetin was lost. Traditional preservation of crushed lingonberries in their own juice caused a considerable (40%) loss of quercetin. Only 15% of quercetin and 30% of myricetin present in unprocessed berries were retained in juices made by common domestic methods (steam-extracted black currant juice, unpasteurized lingonberry juice). Cold-pressing was superior to steam-extraction in extracting flavonols from black currants. During 9 months of storage at 20 C, quercetin content decreased markedly (40%) in bilberries and lingonberries, but not in black currants or red raspberries. Myricetin and kaempferol were more susceptible than quercetin to losses during storage.     

基于特征组合与SVM的小粒种咖啡缺陷生豆检测

缺陷生咖啡豆显著影响商品咖啡豆品质及定价,其分选剔除是咖啡豆烘焙前的重要工作环节。目前缺陷豆的检测、分选及剔除主要由人工操作完成,耗时、费力且主观性大。该研究采用机器视觉技术提取咖啡豆轮廓、颜色和纹理3类特征,使用单一类别特征和不同类别特征进行组合,运用网格搜索确定支持向量机（Support Vector Machine,SVM）分类模型参数,通过k折交叉验证试验对比SVM模型性能,运用皮尔逊相关系数进行特征筛选,找到检测缺陷生咖啡豆的较优特征组合。为说明SVM检测模型的有效性,选用随机森林（Random Forests,RF）、极端随机树（Extremely Randomized Trees,ERT）、逻辑回归（Logistic Regression,LR）、LightGBM、XGBoost和CatBoost算法进行较优特征组合的对比试验。结果表明：包括轮廓、颜色和纹理3类14个特征的组合是较优特征组合,其SVM检测模型的平均准确率、平均精度、平均召回率、平均F1值分别为84.9%、85.8%、82.3%、84.0%,效果均明显优于2类特征组合和单一类别特征的检测模型,SVM检测模型的准确率和F1值相比随机森林、极端随机树、逻辑回归、LightGBM、XGBoost和CatBoost分别提高4.7和4.8,3.4和4.0,5.6和7.2,3.0和3.0,3.5和4.2,2.6和2.6个百分点。较优特征组合的SVM缺陷生咖啡豆检测模型检测缺陷类型较全面,识别准确率高,可实际应用于小粒种生咖啡豆智能化分选装备。     

Residue levels, decline curves, and plantation distribution of procymidone in green beans grown in greenhouse

Residue levels and degradation rates of procymidone residues were studied in green beans grown in a greenhouse. Experiments were planned to also assess the influence of planting density on the behavior of procymidone residues on this type of crop. The study was carried out in four random blocks considering three sub-blocks of different planting densities into each block. Plants were sprayed with Sumisclex 50 WP (1077.5 g of ai/ha) 52 days after the transplantation, and sampling was carried out daily during two different periods of 6 and 5 consecutive days, respectively, around the two harvest days (days 12 and 28 after the treatment). Residue levels of procymidone were determined by using the Luke extraction method and GC-NPD. The average residue levels of procymidone in the overall planting (mean of 12 determinations) were below 2 mg/kg (European maximum residue limit) for all the sampling days, obtaining values of 1.01 +/- 0.55 and 0.37 +/- 0.10 mg/kg, respectively, at the two harvest days. The decline behavior of procymidone residues in the overall plantation and in each block could be described as a pseudo-first-order reaction, obtaining half-life values (t(1/2)) of 10-11 days in all cases. The calculated residue level at the preharvest time (5 days) in the overall plantation was 1.7 mg/kg, but this value in the blocks depended on the block position along the greenhouse and ranged from 2.3 to 0.9 mg/kg. In this work, additional data on the residual behavior of the fungicide pyrazophos in green beans were also obtained.     

Influence of critical storage temperatures on degradative pathways of pigments in green beans (Phaseolus vulgaris cvs. Perona and boby)

In this work a study of critical storage temperatures on pigment degradation of green beans (Phaseolus vulgaris, cvs. Perona and Boby) was conducted. In this way, green beans kept better quality at 4 degrees C than either 8 or 12 degrees C, maintaining a bright green color and good texture. Nevertheless, temperatures of 4 degrees C induced chilling injury (CI) after eight days of storage, which became evident when the pods were transferred to 20 degrees C. Cold storage temperatures, 12, 8, and 4 degrees C, produced different changes on the green beans chlorophyll profile. Green beans of both cultivars, Perona and Boby, stored at 4 and 12 degrees C showed a continuous degradation of chlorophyll pigments during storage, while samples stored at 8 degrees C showed an increase of chlorophyll content at the first 15 days. Carotenoid pigments also suffered different changes during cold storage. Perona was the green beans cultivar which maintained the higher level of lutein, mainly when samples were stored at the most suitable temperature (8 degrees C).     

Role of water state and mobility on the antiplasticization of green and roasted coffee beans

The effect of water on "antiplasticization" and plasticization of green and roasted coffee was studied by textural analysis, sorption isotherms, differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). From BET monolayer value to a(w) = 0.61 and 0.75 for green and roasted coffee, respectively, the solid matrix hydration occurred and water induced hardening. Very short NMR T(2) values and the concomitant absence of any DSC endothermic peak assignable to water freezing were observed at these a(w) values. When solid matrix hydration was completed, water started to act as a plasticizing agent, the compressive modulus started to decrease, and NMR revealed the appearance of a new proton pool with increased mobility. According to DSC, only when the plasticizing effect became important did water present enough mobility to freeze. Above this moisture value (a(w) = 0.78 and 0.86 for green and roasted coffee, respectively), water determined a decrease of bean hardness and a further decrease of the elastic modulus.     

Effect of salt stress on nitrogen fixation by different cultivars of green beans

Nitrogen fixation by three cultivars of green beans (Phaseolus vulgaris L., cv. ‘Tender Improved’, ‘Slim Green’, and ‘Kentucky Wonder') was investigated under normal (control = 0.3 bars osmotic pressure) and NaCl salinized (3.0 bars osmotic pressure) conditions. The study was carried out in a greenhouse with a sand culture technique, using a system which automatically recirculated a modified complete Hoagland nutrient solution with only 5 ppm N. Nitrogen was added as K¹⁵NO₃ to the culture solution. Plants were harvested three times (10, 20, and 30 days after the completion of the salt and N treatments). Plant parts (shoots and roots) were evaluated separately for dry matter production, total‐N concentration (%), total‐N content (mg/plant part), total‐N fixation (mg/plant part), and percentage of total‐N fixation. Salt stress significantly decreased dry matter production, total‐N content (uptake plus fixed), percent of total‐N fixed (based on the total‐N content of plant parts), and amount of total‐N fixed by plants. Among the three cultivars, Slim Green produced the lowest dry matter, fixed the least amount of N₂, and had the lowest fixed‐N percentage for any corresponding treatment, particularly under NaCl stress conditions.     

果袋透气性对苹果黑点病、Pb及总酸含量的影响

选择9种代表性的双层果袋进行试验,果实采收后10 d内对果实各项指标按GB10651－1989进行检测,结果发现：果袋的透气性对苹果果实黑点病指数、总酸含量及重金属Pb含量有显著影响。果袋透气性越大,果实黑点病指数越小;果实中总酸含量越高,口感越好;果实中Pb的含量越大(同种条件下),安全风险越高。在保证苹果安全的前提下,苹果黑点病指数越低越好,总酸含量越高越好,结合中国绿色苹果生产标准及现有的技术水平,宜选用透气性为3～5 μm/(Pa·s)的果袋。     

Characterization of the temperature activation of pectin methylesterase in green beans and tomatoes

Low-temperature blanching of vegetables activates the enzyme pectin methylesterase (PME), which demethylates cell wall pectins and improves tissue firmness. This temperature activation of PME has been investigated by measuring the formation of methanol in intact tissue of green beans and tomatoes. Rates of methanol formation at temperatures of 35-65 degrees C were obtained by measuring the release of methanol from thin slices of tomato pericarp or green bean pod material. Activation energies of 112 and 97 kJ mol(-1) were calculated for PME activity in green beans and tomatoes, respectively. These activation energies indicate that the rate of pectin demethylation at 65 degrees C will be nearly 100 times that at 25 degrees C. PME activity was also determined titrimetrically using a solubilized form of the enzyme and purified pectin at temperatures from 30 to 60 degrees C. Under these conditions, much lower activation energies of 37 and 35 kJ mol(-1) were obtained for green beans and tomatoes, respectively. Methanol accumulation during heating of whole intact green beans was also determined and yielded an activation energy similar to that obtained with sliced beans. Whole green beans held at room temperature did not accumulate any methanol, but sliced or homogenized beans did. If whole beans were first heated to 45 degrees C and then cooled, methanol accumulation was observed at room temperature. These results indicate that two factors contribute to the observed high rate of pectin de-esterification during low-temperature blanching: (1) An irreversible change, causing PME to become active, occurs by heating to > or = 45 degrees C. (2) The high activation energy for pectin de-esterification means that the rate of de-esterification increases substantially with increasing temperature.     

Influence of potassium on uptake and distribution op cesium in bush beans

Bush beans, Phaseolus vulgaris L. cv. Improved Tendergreen, were grown for 18 days in 3700 ml. nutrient solutions in a factorial experiment involving 3 levels of K (10^‐2, 10^‐3, 10^‐4N) and 3 levels of Cs (10^‐4, 5 x 10^‐5, 10^‐5N). Mild K deficiency was observed for the low K level but no yield differences were due to Cs. Increasing K markedly decreased the Cs concentrations in all plant parts. The relative uptake of K vs Cs was not influenced by Cs but was by K. The concentration ratio (C.R.) for K in trifoliate leaves varied from 99 (high K) to 7315 (low K). The C.R, for Cs in trifoliate leaves varied from 8,67 (high K) to,0.96 (low K). Potassium was translocated to trifoliate leaves from 89 to 843 times that of Cs. The “Y”; values for Cs in plant parts was consistently near 1 meaning that Cs uptake was directly proportional to its concentration in the nutrient solution. The “Y”; values for K in plant parts were around 0.5 for 10^‐3/10^‐4N K but only about 0,2 for 10^‐2/10^‐3N K. Roots accumulated about 6 times more Cs than did leaves while K was quite uniformly distributed among plant parts. The uptake relationship for K and Cs then was vastly different indicating that K would not likely be a good carrier of radiocesium in food chains.     

Screening on the occurrence of ochratoxin A in green coffee beans of different origins and types

Since to our knowledge no data are available in the literature regarding the influence of green coffee type and origin on ochratoxin A (OTA) content, determinations were carried out in order to assess the level of OTA contamination in green coffee samples of different provenience. A total of 162 samples of green coffee beans from various countries (84 from Africa, 60 from America, and 18 from Asia) were analyzed for OTA. Both the amount and the variability of OTA levels were tested as a function of green coffee provenience. The results showed that 106 of the overall samples were positive for OTA, with concentration ranging from 0 to 48 microg/kg (ppb). In particular, it was possible to verify that African samples were more contaminated with respect to samples of other origin in terms of frequency and level of OTA; the highest concentrations observed were 18 and 48 microg/kg in two samples from The Congo.     

Effect of processing conditions on phytic acid, calcium, iron, and zinc contents of lime-cooked maize

Tortillas are made by cooking maize in a lime solution during variable times and temperatures, steeping the grain for up to 12 h, washing and grinding it to a fine dough, and cooking portions as flat cakes for up to 6 min. The effects of the main processing steps on the chemical composition, nutritive value, and functional and physicochemical characteristics have been areas of research. The present work evaluates the effect of lime concentration (0, 1.2, 2.4, and 3.6%) and cooking times (45, 60, and 75 min) on phytic acid retention of whole maize, its endosperm, and germ, as well as on the content of calcium, iron, and zinc on the same samples. The effects of steeping time and temperature and steeping medium on the phytic acid of lime-cooked maize were also studied. Finally, phytic acid changes from raw maize to tortilla were also measured. The results indicated that lime concentration and cooking time reduce phytic acid content in whole grain (17.4%), in endosperm (45.8%), and in germ (17.0%). Statistical analyses suggested higher phytic acid loss with 1.2% lime and 75 min of cooking. Cooking with the lime solution is more effective in reducing phytic acid than cooking with water. Steeping maize in lime solution at 50 degrees C during 8 h reduced phytic acid an additional 8%. The total loss of phytic acid from maize to tortilla was 22%. Calcium content increased in whole maize, endosperm, and germ with lime concentration and cooking and steeping times. The increase was higher in the germ than in the endosperm. The level, however, can be controlled if steeping of the cooked grain is conducted in water. Iron and zinc contents were not affected by nixtamalization processing variables but were affected in steeping.     

Processing strawberries to different products alters contents of vitamin C, total phenolics, total anthocyanins, and antioxidant capacity

Strawberries were processed to juice, nectar, wine, and puree. For investigation of the antioxidant capacity as well as the contents of ascorbic acid, total phenolics and total anthocyanins, samples were taken after different stages of production to determine the effects of processing. The content of vitamin C was measured spectrophotometrically. The total phenolic content was analyzed by using the Folin-Ciocalteu method, and the amount of total anthocyanins was determined by using the pH-differential method. Two different methods-the trolox equivalent antioxidant capacity assay and the ferric reducing antioxidant power test-were used to determine the hydrophilic antioxidant capacity. This study showed the decrease of all investigated parameters within processing strawberries to different products. The content of ascorbic acid decreased with production time and processing steps, especially during heat treatment. The investigations on total phenolics in strawberry products proved fining to be a mild method to clarify berry juices and wines without removing high amounts of total phenolics. Fermentation did not lead to heavy losses of total phenolics, probably due to polymerization and condensation of monomer phenolics such as anthocyanins. Total anthocyanins and the hydrophilic antioxidant capacity decreased while using high temperatures. Anthocyanins also decreased considerably during the processing of wines, mainly caused by fermentation and pasteurization.     

Glucoraphanin and 4-hydroxyglucobrassicin contents in seeds of 59 cultivars of broccoli, raab, kohlrabi, radish, cauliflower, brussels sprouts, kale, and cabbage

The importance of dietary sulforaphane in helping maintain good health continues to gain support within the health-care community and awareness among U.S. consumers. In addition to the traditional avenue for obtaining sulforaphane, namely, the consumption of appropriate cruciferous vegetables, other consumer products containing added glucoraphanin, the natural precursor to sulforaphane, are now appearing in the United States. Crucifer seeds are a likely source for obtaining glucoraphanin, owing to a higher concentration of glucoraphanin and the relative ease of processing seeds as compared to vegetative parts. Seeds of several commonly consumed crucifers were analyzed not only for glucoraphanin but also for components that might have negative health implications, such as certain indole-containing glucosinolates and erucic acid-containing lipids. Glucoraphanin, 4-hydroxyglucobrassicin, other glucosinolates, and lipid erucic acid were quantified in seeds of 33 commercially available cultivars of broccoli, 4 cultivars each of kohlrabi, radish, cauliflower, Brussels sprouts, kale, and cabbage, and 2 cultivars of raab.     

Heavy metal, total arsenic, and inorganic arsenic contents of algae food products

The total arsenic, inorganic arsenic, lead, cadmium, and mercury contents of 18 algae food products currently on sale in Spain were determined. The suitability of the analytical methodologies for this type of matrix was confirmed by evaluating their analytical characteristics. The concentration ranges found for each contaminant, expressed in milligrams per kilogram of dry weight, were as follows: total arsenic, 2.3-141; inorganic arsenic, 0.15-88; lead, < 0.05-1.33; cadmium, 0.03-1.9; and mercury, 0.004-0.04. There is currently no legislation in Spain regarding contaminants in algae food products, but some of the samples analyzed revealed Cd and inorganic As levels higher than those permitted by legislation in other countries. Given the high concentrations of inorganic As found in Hizikia fusiforme, a daily consumption of 1.7 g of the product would reach the Provisional Tolerable Weekly Intake recommended by the WHO for an average body weight of 68 kg. A more comprehensive study of the contents and toxicological implications of the inorganic As present in the algae food products currently sold in Spain may be necessary, which might then be the basis for the introduction of specific sales restrictions.     

Comparative contents of dietary fiber, total phenolics, and minerals in persimmons and apples

Dietary fibers, major phenolics, main minerals, and trace elements in persimmons and apples were analyzed and compared in order to choose a preferable fruit for an antiatherosclerotic diet. Fluorometry and atomic absorption spectrometry following microwave digestion were optimized for the determination of major phenolics and minerals. Total, soluble, and insoluble dietary fibers, total phenols, epicatechin, gallic and p-coumaric acids, and concentrations of Na, K, Mg, Ca, Fe, and Mn in whole persimmons, their pulps, and peels were significantly higher than in whole apples, pulps, and peels (P < 0.01-0.0025). Conversely, the contents of Cu and Zn were higher in apples than in persimmons. In persimmons and apples all of the above components were higher in their peels than in whole fruits and pulps. The relatively high contents of dietary fibers, total and major phenolics, main minerals, and trace elements make persimmon preferable for an antiatherosclerotic diet.     

Impact of different stages of juice processing on the anthocyanin, flavonol, and procyanidin contents of cranberries

Juice is the most common form in which cranberries are consumed; however there is limited information on the changes of polyphenolic content of the berries during juice processing. This study investigated the effects of three different pretreatments (grinding plus blanching; only grinding; only blanching) for cranberry juice processing on the concentrations of anthocyanins, flavonols, and procyanidins throughout processing. Flavonols and procyanidins were retained in the juice to a greater extent than anthocyanins, and pressing resulted in the most significant losses in polyphenolics due to removal of the seeds and skins. Flavonol aglycones were formed during processing as a result of heat treatment. Drying of cranberry pomace resulted in increased extraction of flavonols and procyanidin oligomers but lower extraction of polymeric procyanidins. The results indicate that cranberry polyphenolics are relatively stable during processing compared to other berries; however, more work is needed to determine their fate during storage of juices.     

Influence of soil-drying under field conditions on exchangeable manganese,cobalt, and copper contents

Abstract

The changes in the exchangeable Mn (Ex-Mn), exchangeable Co (Ex-Co), and exchangeable Cu (Ex-Cu) contents by air-drying of soils were reported in our previous paper. The drying effect, however, was not analyzed in the field. The objective of this study was to investigate the influence of soil-drying under field conditions on Ex-Mn, Ex-Co, and Ex-Cu levels. Two paddy soils (Tsukuba and Yawara) were collected at four different soil depths (0?1, 1?5, 5?10, and 10?20 cm) under three different soil moisture conditions i.e., after harvest, after successive sunny days and after rainy days. After sunny days, Ex-Mn and Ex-Co contents in the surface soil layer markedly increased and drastically decreased after rainfall, while they remained almost unchanged in the lower soil layers. Ex-Cu contents slightly increased in the surface soil layer after sunny days. A similar tendency was observed in soil column experiments. The contents of Ex-Mn, Ex-Co, and Ex-Cu increased 12, 12, and 2 times in the upper layer of soil columns that had been sampled from the Yawara field and stored in a dark room for 8 d. The increase of the Ex-Mn and Ex-Co contents in the upper layer could not be explained by the capillary rise of soil water from the lower layers of the columns. In a soil-drying experiment under laboratory conditions, Ex-Mn and Ex-Co contents began to increase when the water content of the Yawara soil was lower than 0.09?0.13 kg kg^?1. The water content of the surface soil of the Yawara field after sunny days was 0.08 kg kg^?1. Ex-Cu content did not change apprecially with the water content. It is concluded that the increase of the Ex-Mn and Ex-Co levels in field surface soils after sunny days can be ascribed to soil-drying. Some of the excess Ex-Mn and Ex-Co is expected to leach down into lower layers due to rain, which may contribute to plant uptake of Mn and Co.     

绿色食品“三产”融合发展路径研究

绿色食品"三产"融合发展是激发绿色食品发展动能的重要抓手。本文分析了黑龙江省绿色食品"三产"融合发展趋势、基本特征和典型经验,以及当前面临的困难和挑战,总结了一些带有规律性的认识,在此基础上,对加快推进绿色食品"三产"融合发展提出了建议。