Retention of folates in cooked,stored and reheated peas,broccoli and potatoes for use in modern large-scale service systems

This study aimed to evaluate retention of folate in vegetables caused by different processes used in modern large-scale service systems and the food industry. The concentration of folates present in raw samples of peas, broccoli and potatoes was measured during different cooking methods, warm and cold holding and reheating. The main folate forms in vegetables, tetrahydrofolates and 5-methyltetrahydrofolates, were analysed using a validated high-performance liquid chromatography (HPLC) method.     

Voltammetric determination of the herbicides nitralin and oryzalin in agricultural formulations,vegetables and grape juice samples

A sensitive method for the determination of the herbicides nitralin and oryzalin by adsorptive stripping voltammetry (AdSV) at a hanging mercury drop electrode (HMDE) (pH 6.0) was described. The cyclic voltammograms demonstrate the adsorption of these compounds at the mercury electrode. A symmetric study of the various operational parameters that affect the stripping response was carried out by differential pulse voltammetry. With an accumulation potential of −0.5 V and a 80 s accumulation time, the limit of detection was 2.47 × 10⁻⁸ mol/L and 1.5 × 10⁻⁸ mol/L, the relative standard deviation (n = 10), correlation coefficient values 1.14%, 0.998, 1.48%, 0.999 at concentration levels of 8.3 × 10⁻⁸ mol/L to 1.5 × 10⁻⁶ mol/L and 2 × 10⁻⁸ mol/L to 1.0 × 10⁻⁵ mol/L for both compounds. The degree of interference of some other pesticides on the differential pulse adsorptive stripping signal for nitralin and oryzalin was evaluated. Finally the proposed method was applied for determination of nitralin and oryzalin in agricultural formulations, vegetables and grape juice samples.     

Enzymatic Firming of Processed Red Pepper by Means of Exogenous Pectinesterase

Abstract

The objective of this investigation was to demonstrate that the firmness of a commercial vegetable product, diced and frozen red pepper (Capsicum annum var. Sendt), could be improved by the use of exogenous pectinesterase in an industrially relevant process. The diced pepper pieces 10?×?10?×?7?mm³ were infused under vacuum with a commercially available pectinesterase. The range of optimal process conditions was: 15–20°C, 45?min infusion time, a 10–25?mM CaCl₂ infusion brine, a w/w ratio of pepper fruit to infusion brine of 1.5:1, and an enzyme dosage of 30–60 pectinesterase units (PEU) per kg pepper fruit. The firmness as measured by back extrusion was improved by a factor of two to three. The effect of firming was robust and conserved after freezing and heating in a simulated household cooking process. The firming process seems easily adaptable to industrial conditions and may be applicable to other vegetable and fruit products.     

螺旋杀青机的热力学分析及结构参数的确定

通过对螺旋杀青机的热力学过程的分析，得出杀青机满足果蔬杀青效果所应具有的机械参数，即杀青机长度L，杀青机的外箱体的下圆弧半径R2，滚筒的外径R1，内径r等，为设计杀青机CAD的专用软件奠定了理论基础。     

Carotenoids and chlorophylls in processed xanthophyll-rich food

Processing of food modifies nutrient contents and food matrices. The present analyses provide information about the effects of heat steam sterilization (HSS), high pressure processing (HPP) and common household cooking on the stability of carotenoids and chlorophylls in spinach, parsley, dill and kale. For HSS, samples were heated in an autoclave for 5, 10, 15 and 20 min at 121 °C. Additionally, one sample was treated via HPP at 200, 400 and 600 MPa for 5, 10 and 40 min at room temperature. Carotenoid and chlorophyll contents were determined by reversed-phase HPLC. Lutein was the most abundant carotenoid in all samples. Furthermore, violaxanthin, zeaxanthin, β-carotene, chlorophylls a and b were quantified. Thermal treatment via HSS led to a significant decline of contents of lutein, chlorophylls a and b. HPP did not reduce the amounts of xanthophylls and chlorophylls. Conclusively, HPP seems to be a good alternative to HSS for the preservation of xanthophyll-rich food.     

Dietary Nitrate,Nitric Oxide,and Cardiovascular Health

Emerging evidence strongly suggests that dietary nitrate, derived in the diet primarily from vegetables, could contribute to cardiovascular health via effects on nitric oxide (NO) status. NO plays an essential role in cardiovascular health. It is produced via the classical L-arginine–NO-synthase pathway and the recently discovered enterosalivary nitrate–nitrite–NO pathway. The discovery of this alternate pathway has highlighted dietary nitrate as a candidate for the cardioprotective effect of a diet rich in fruit and vegetables. Clinical trials with dietary nitrate have observed improvements in blood pressure, endothelial function, ischemia-reperfusion injury, arterial stiffness, platelet function, and exercise performance with a concomitant augmentation of markers of NO status. While these results are indicative of cardiovascular benefits with dietary nitrate intake, there is still a lingering concern about nitrate in relation to methemoglobinemia, cancer, and cardiovascular disease. It is the purpose of this review to present an overview of NO and its critical role in cardiovascular health; to detail the observed vascular benefits of dietary nitrate intake through effects on NO status as well as to discuss the controversy surrounding the possible toxic effects of nitrate.     

Second order derivative spectrophotometric method for determination of vitamin C content in fruits,vegetables and fruit juices

A second-order derivative UV spectrophotometric method for determination of vitamin C [ascorbic acid (AA)] content in a variety of natural samples is described. The method is based on the measurement of a peak–baseline amplitude in the second derivative of the AA spectrum at 267.5 nm. The following corresponding regression equation was obtained within the concentration range 2×10^-5 to 1×10^-4 M AA (3.5–17.6 g/cm³ AA) in 1.0 M HCl solution: ²D_267.5=2.420×10⁴ c+0.025; the correlation coefficient was 0.9993 and the detection limit 4.2×10^-6 M. The results obtained by analysing 21 different species of fruits, vegetables and juices indicated a possibility for a more extensive application of the proposed method. This method is rapid, simple and requires no pretreatment of the analysed material, which makes it suitable for routine analyses. The reliability of the method was confirmed by comparative determinations with the generally accepted 2,6-dichloroindophenol method.     

Recent Application of Modified Atmosphere Packaging (MAP) in Fresh and Fresh-Cut Foods

Modified atmosphere packaging (MAP) has been applied in the food industry for about 90 years to extend shelf life and maintain quality of fresh and fresh-cut foods. Recently, MAP has experienced a rapid development in both scientific and industrial communities, which was one of the most appropriate and practical technologies for packaging fresh and fresh-cut produce. This paper reviews some recent developments of newly emerged MAP systems such as high-oxygen MAP, controlled MAP, and intelligent MAP and provides an overview of MAP applications for fresh and fresh-cut fruits, vegetables, mushrooms, meat, and aquatic products.     

Development of vegetable composition databases based on available data for probabilistic nutrient and contaminant intake assessments

Dietary intake assessment can be considered as a two-step process consisting of collecting and evaluating food composition data, and combining these data with food consumption data. The purpose of this study was to develop databases of nutrient and contaminant concentrations in organic and conventional vegetables and potatoes based on internationally available secondary data. Databases, as described here, are important in (1) comparing the composition of similar foods (organic versus conventional) and (2) assessing probabilistically the combined intake of nutrients and contaminants when nutritional and toxicological dimensions of food consumption are being studied simultaneously.     

保鲜技术在鲜切果蔬中的应用

简要介绍了鲜切果蔬的发展现状,重点分析了鲜切果蔬常见的保鲜技术及存在的问题,提出了新型保鲜技术在鲜切果蔬的应用构想,展望了鲜切果蔬的应用前景。