2013—2014年广东省基地蔬菜重金属污染状况调查

目的了解广东省基地蔬菜中各类蔬菜重金属的污染状况及分布特点。方法 2013—2014年从广东省21个地市(4个地理区域:粤北、粤东、粤西、珠三角)的蔬菜种植基地采集8类615份蔬菜进行铅、镉、汞、砷的检测。结果广东省蔬菜中重金属污染以铅和镉为主,其中铅污染的主要蔬菜品种是叶菜类蔬菜,尤其是生菜;而镉污染的主要蔬菜品种是茄果类蔬菜,尤其是茄子。铅在广东省4个地区均有一定程度的污染,而镉含量较高的地区是粤北(韶关)和粤西(云浮)地区。结论广东省基地蔬菜中重金属污染程度总体较轻,需重点关注粤北和粤西地区的铅和镉的污染,加强对重点区域重点品种的监测。     

An investigation into the dietary fibre content of named varieties of carrot at different developmental ages

The carrot, Daucus carota, is a commonly used vegetable which has changed in appearance due to plant breeding programmes. The development of the carrot can be divided into a period of rapid increase in fresh weight, a stage of constant fresh weight and a stage of floral development and decrease in fresh weight. An analysis of the dietary fibre content of the carrot and its chemical composition has been made, using the varieties Altrincham, Chantenay, Nantes and Scarlet Perfection, at different developmental stages. Fibre was measured as prepared fibre, NDF, ADF, cellulose and lignin. No differences were found between varieties except those due to the different developmental rates of each variety. Within each variety the ADF content increased during late stage 2 and the increase was apparently due to the cellulose component of the ADF. Despite the differences, however, in carrot fresh weight between varieties and also within each variety there is no difference in any fibre component of carrot per 100 g fresh weight.     

不同利用方式对几种根茎类蔬菜亚硝酸盐含量的影响

以山药、胡萝卜、莲藕为实验材料,研究不同贮藏条件、烹饪方法和熟菜保存方式下3种根茎类蔬菜中亚硝酸盐含量的变化。结果表明：无论常温还是低温贮藏,贮藏7d内,3种根茎类蔬菜的亚硝酸盐含量均呈现先增加后降低的趋势,虽然常温贮藏的亚硝酸盐含量高于低温贮藏,但两者均小于4mg/kg。不同烹饪加工可显著降低3种蔬菜的亚硝酸盐含量,煮制、炒制、烤制加工方式的亚硝酸盐含量降幅分别为70%～83%、66%～80%和33%～55%,其中胡萝卜的亚硝酸含量降幅最大,莲藕的最小。低温和常温保存的熟菜,菜体中亚硝酸盐含量随时间延长而增加,保存到48h时,3种菜体的亚硝酸盐含量均小于4mg/kg,且低温远低于常温(前者最大为1.03mg/kg,后者最大为1.98mg/kg),参照食用的亚硝酸盐标准,低温(4℃)和常温(20℃)保存的熟制根茎类蔬菜食用安全期均达48h,且煮制和炒制加工的熟菜优于烤制。     

Physical and nutritional properties of edamame seeds as influenced by stage of development

Changes in physical, chemical and anti-nutritional characteristics of two vegetable soybean varieties (‘Asmara’ and ‘Mooncake’) during seed development were investigated. Pods were sampled weekly for 6 weeks starting from developmental stage 5 (R5) to 8 (R8). Changes over time in measured attributes were similar but the rate of change differed among the two varieties. In both varieties seed moisture content and intensity of green color decreased as seed developed with the most significant decline observed in the last 2 weeks of sampling. Seed weight peaked at R6 then gradually decreased thereafter, while seed hardness increased throughout the sampling period with ‘Asmara’ recording significantly higher seed hardness at R8. For both varieties, protein accumulation occurred mostly in the later stages, while significant lipid accumulation was observed in the early stages of development. Among the sugars, fructose content decreased with seed development, sucrose content increased to R6 before decreasing, and there was rapid accumulation of raffinose and stachyose in the last 2 weeks of sampling. Total phenolic content decreased between R5 and R6 but increased with further seed development. Tannin and phytate content in seed increased throughout the sampling period. Changes in trypsin inhibitory activity varied with variety reaching a maximum at R6 for ‘Asmara, and closer to maturation for “Mooncake’. Our data provide physical, chemical and anti-nutritional basis for harvesting vegetable soybean at R6 namely: peak seed weight and sucrose content, lower oligosaccharide and anti-nutrients values and intense green color.     

气调冷藏集装箱对蔬菜贮藏的保鲜效果

为探讨气调冷藏集装箱的保鲜效果,以常见蔬菜小白菜、油麦菜、芹菜、菠菜为试材,在1 ℃条件下,分别用气调冷藏集装箱与普通冷库贮藏,气调环境为5%±1% O₂、95%±1% N₂,相对湿度为90%±5%,乙烯脱除模块每天凌晨脱除0.5 h,臭氧杀菌模块每天灭菌一次,浓度2 g·min?1,时间是10 min,而普通冷库除冷藏外不再增加其他措施。通过测定贮藏期间蔬菜的失重率、可溶性固形物、可滴定酸、抗坏血酸、呼吸强度、丙二醛、叶绿素指标,评价设备保鲜性能。结果表明,与普通冷库相比,在45 d贮藏期内,气调冷藏集装箱明显能有效防止蔬菜水分的散失,维持较高的可溶性固形物、可滴定酸含量,在一定程度上抑制了果蔬的呼吸作用,降低抗坏血酸、叶绿素的消耗,减轻叶片细胞膜质过氧化的程度,能有效延缓蔬菜腐烂变质的时间,保持蔬菜较好的贮藏品质。因此,气调冷藏集装箱对大批量蔬菜的贮藏具有良好的应用前景。     

对酱腌菜传统生产工艺的改革探讨

该文介绍了对酱腌菜传统生产工艺改革的主要内容，包括蔬菜收购方式、酱腌菜原料的品种、蔬菜腌渍工艺、蔬菜咸坯贮存方法、酱渍工艺等。实践表明几次改革对提高产品质量，延长保存期收到了较好的效果。     

Children’s liking and intake of vegetables: A school-based intervention study

This study investigated effects on vegetable liking and intake gained from exposing children to snack vegetables of different liking levels. In total, 345 9–11-year-old children participated. The intervention consisted of two exposure periods. First, children were either exposed to a neutrally liked vegetable (cauliflower), a mixture of a neutrally liked and a liked (sugar snap peas) vegetable, or a mixture of a neutrally liked and a disliked (celery) vegetable. In the second, period all children were served all vegetables. Intake of individual vegetables was measured daily. Liking was assessed before and after exposures and at a subsequent follow-up. Liking for most vegetables decreased during the exposure periods but tended to recover somewhat during follow-up. Intake of all vegetables was either stable or decreased during the intervention, no increases were observed. Intake levels depended on type of vegetable servings: When served with a liked vegetable, children consumed more of a neutrally liked vegetable than when served alone (p = 0.0005) or together with a disliked vegetable (p = 0.005).     

NUTRIENT QUALITY OF SELECTED VEGETABLES PREPARED BY CONVENTIONAL AND COOK-FREEZE METHODS

Selected vegetables (spinach, broccoli, sweet potatoes, and collard greens) prepared in 2.27 kg (5 lb) quantities by boiling, were frozen and stored for six months at ?18°C. Zinc, iron, β-carotene, and ascorbic acid were determined on the raw vegetable immediately after cooking and after reheating in a microwave oven subsequent to 6 months frozen storage. The greatest nutrient loss occurred for water soluble nutrients during boiling. Nutrient comparison between cooked samples (conventional method) and samples microwaved after 6 months frozen storage (cook-freeze method) indicated that differences existed only in ascorbic acid content of spinach. Data indicated that vegetables prepared by cook-freeze, a method used by health care institutions, were generally equal in nutrient quality to conventionally prepared vegetables.     

Selection and characterization of mixed starter cultures for lactic acid fermentation of carrot, cabbage, beet and onion vegetable mixtures

An evaluation of various lactic acid bacteria (LAB) for the fermentation of cabbage, carrot and beet-based vegetable products was carried out. As part of a screening process, the growth of 15 cultures in a vegetable juice medium (VJM) was characterized by automated spectrophotometry. Acidification patterns as well as viability during storage of the LAB were also established. There were greater differences between the pure cultures than the mixed ones with respect to growth in VJM and viability during storage. Reductions in viable cell counts during storage of the fermented VJM occurred more rapidly with a Leuconostoc strain than for pediococci or lactobacilli. Inoculation of vegetables was carried out with cultures of Lactobacillus plantarum NK-312, Pediococcus acidilactici AFERM 772 and Leuconostoc mesenteroides BLAC which were rehydrated in a brine. This rehydration procedure was not detrimental to viability. During fermentation of a carrot/cabbage vegetable mix, sugar metabolism was characterized by the assimilation of both glucose and fructose, but sugars remained in the fermented vegetables when acidification stopped. The pH in the LAB-inoculated vegetables after 72 h at 20 degrees C was significantly lower (by 0.2 units) than the uninoculated control. Inoculation with LAB designed for silage fermentation resulted in the inhibition of acetic acid production, and reduced the production of ethanol during fermentation. The selection process on VJM enabled the preparation of a mixed culture that was more rapid than the silage inoculants in acidifying the medium and was more effective in reducing the production of gas during the fermentation and storage of the fermented vegetables.     

不同烹饪与冷却方法对冷配送中式快餐中3种绿色蔬菜品质的影响

目的探究烹饪及冷却方法对冷配送中式快餐中绿色蔬菜的品质影响。方法以西兰花、青椒及青刀豆为研究对象,分别对其进行热烫、微波、急炒烹饪,再分别进行自然冷却、冷风冷却及冷水冷却,检测其失重率、亚硝酸盐含量、叶绿素含量及可滴定酸含量等指标的变化。结果热烫的西兰花重量不减反增,青刀豆及青椒急炒时失重率最高。3种蔬菜热烫后使用不同的方法冷却,其亚硝酸盐含量均上升。所有处理都使3种蔬菜中的叶绿素含量显著降低。冷却方式不会影响3种蔬菜中的可滴定酸含量,而烹饪方式却有影响。结论烹饪及冷却方式对中式快餐中的绿色蔬菜品质有一定的影响,且与蔬菜品种有关。     

Radiation Processing of Minimally Processed Pineapple (Ananas comosus Merr.): Effect on Nutritional and Sensory Quality

ABSTRACT:  Radiation processing of minimally processed pineapple at a dose of 2 kGy was investigated. Effect of this treatment on different quality parameters like vitamin C content, total carotenoids content, sensory attributes, texture, and color was determined over a storage period of 12 d at 8 to 10 °C. Results showed that the irradiation treatment showed no significant effect ( P > 0.05) on total vitamin C content of pineapple samples but a significant decrease ( P ≤ 0.05) in vitamin C during storage period in both controls as well as irradiated samples was observed. However, total carotenoids were not affected by irradiation and were stable during the whole storage period as well ( P > 0.05). Sensory evaluation studies revealed that irradiation had no significant effect ( P > 0.05) on the ratings of any of the sensory attributes of pineapple samples. Taste panelists could not differentiate between control and irradiated samples. Textural studies showed no significant effect ( P > 0.05) of irradiation as well as storage period on the firmness of the central edible region of pineapple samples. Color attributes of both control and irradiated samples showed slight variation during the storage period of 12 d. However, irradiation at 2 kGy did not have a significant effect ( P > 0.05) on all color coordinates. Thus, radiation processing with 2 kGy did not affect significantly the nutritional value as well as the sensory quality of minimally processed pineapple samples.     

不同品种石榴籽油油脂品质对比分析

为比较不同品种石榴籽油的油脂品质差别,以10个品种的石榴籽油为样本采用气相色谱技术(GC)分析了其主要脂肪酸组成,采用国标方法测定其过氧化值(POV)和碘值,并研究了储存期石榴籽油的POV变化。结果显示,10个品种的石榴籽油棕榈酸含量为1.77%～3.01%,油酸含量为1.20%～5.12%,亚油酸含量为1.67%～2.95%,石榴酸含量为52.54%～89.78%;POV为0.002 25～0.008 6 g/100 g之间,碘值为143.4～162.2 gI/100 g;储存期石榴籽油POV存在跃变现象。表明不同品种石榴籽油在品质上存在一定的差别,其中石榴酸是各品种的主要脂肪酸并且品种间含量差异较大,都属于高不饱和植物油,保健价值高,但容易氧化变质,不耐储存。     

A systemic approach to qualitative changes in the stored-wheat ecosystem: Prediction of deterioration risks in unsafe storage conditions in relation to relative humidity level, infestation by Sitophilus oryzae (L.), and wheat variety

A multidimensional laboratory trial was carried out to identify the primary causes of changes in quality traits in the stored-grain ecosystem to reveal critical storage condition boundaries that may endanger grain quality retention. Qualitative criteria were followed on grain batches from 3 wheat varieties which were stored for 160 d at temperature of 22-23 °C, at two different relative humidities, and with or without infestation by the rice weevil Sitophilus oryzae, to build a multivariate data matrix. The interactions between biotic deteriorative factors and qualitative trait changes were explored through a principal component analysis (PCA). From the Pearson’s product moment correlation matrix, it was observed that the variables that correlated significantly with insect and fungal species dynamics were: moisture content, hL mass, seed viability, and fat acidity of extracted whole flour. Four factors explained the major part of the variance: storage duration, moisture content, hidden insect infestation density, and fungal contamination level. The rate of increase of the insect population was significantly different between varieties. PCA revealed that the significant difference in qualitative deterioration pattern observed between the three varieties was not related to their hardness but rather to a different relationship between the grain and relative humidity. Germination rate was the first quality factor to decline during the storage period. The technological properties of flour extracted from each variety were not affected before insect population density exceeded 1000 adult insects per kg. The rate of qualitative changes induced by the biotic deterioration factors was processed into a “biodeterioration susceptibility index” (BSI) according to the safe storage time assessed in the present study. This index may be used in IPM approaches to predict the susceptibility of a particular wheat variety to insect and fungal damage during long-term storage.     

Effects of a family-based sensory education on vegetable and fruit variety in children

Several experimental studies implemented in schools have shown that sensory education reduces children’s neophobia and increases their sensory discrimination abilities. However, it is not known whether sensory education has an effect on children’s consumption, particularly on the variety of fruits and vegetables consumed, and whether it is effective when implemented in families.The effect on fruit and vegetable intake of a five months family-based sensory programme was examined in children aged 7–11 (with 32 children in the intervention group and 19 in the control group). The children's parents completed four 24-hour recalls at the beginning and after the intervention to assess their children’s fruit and vegetable intake. Variety indexes were calculated on the basis of the number of different fruits or vegetables consumed during the four 24-hour recalls.The results showed that the vegetable variety decreased in the control group, while it remained stable in the intervention group. No effects of the programme were observed for the fruit variety.The sensory education programme implemented in families prevented the variety of vegetables from decreasing over time. The results of this preliminary study and its long-term effects need to be confirmed by further investigations, with a different methodology than the 24-hour recall.     

Comparison of improved and local maize varieties in the Republic of Benin with emphasis on susceptibility to Sitophilus zeamais Motschulsky

Experiments were conducted to verify differences in agronomic traits and susceptibility to the maize weevil, Sitophilus zeamais, in the field and in traditional maize storage systems between two international improved varieties, which have not been readily accepted by farmers in the Republic of Benin, one partially improved local variety and a local variety obtained from farmers. Factors responsible for differences in susceptibility and suitable screening methods for resistance to the maize weevil were also studied. In the first part of this study the varieties were compared in the field, during field drying and when stored using traditional techniques. The international improved varieties had significantly higher grain yield (60%) but had significantly poorer husk cover. The percentage of damaged ears following field drying, and the numbers of storage pests and grain weight loss after one month of storage were significantly higher in the international improved varieties presumably as a result of poorer husk cover.

In the second part of this study the varieties were compared in a factorial arrangement of three storage forms (undehusked, dehusked and shelled grain) and two infestation methods (free and no-choice). Due to their superior husk cover quality, Benin varieties were significantly more resistant to weevils when infested in the traditional, undehusked storage form than international improved varieties. The smaller-grain, flinty, Benin varieties showed a significantly smaller number of F₁ generation weevils. A significant lengthening of the median development period (MDP) of weevils was observed when maize was stored as dehusked ears compared to shelled grain, particularly on the international improved varieties. No improved vs Benin variety comparisons interacted with free vs no-choice comparisons except for index of susceptibility in the undehusked storage form. Free choice infestations resulted in increased experimental error for number of F₁ weevils, presumably due to a clumped distribution of female weevils during oviposition. When the target farmer's storage system is undehusked ears, it is suggested to use no-choice infestation of undehusked ears as a screening method for elite candidate varieties. An assessment of husk quality and no-choice infestation of shelled grain and/or dehusked maize ears is suggested as more appropriate for preliminary screening of diverse germplasm.     

Characterisation of polyphenols and antioxidant properties of five lettuce varieties and escarole

Salad vegetables could be relevant as dietary sources of natural antioxidants. A better knowledge of their composition can be useful for understanding their potential bioavailability and biological activities. The antioxidant compounds, polyphenols and vitamin C, have been determined in five varieties of lettuce (iceberg, romaine, continental, red oak leaf, lollo rosso) and one variety of escarole (frissé). The polyphenol study by HPLC-DAD-MS/MS ESI allowed the identification of two compounds previously not reported in lettuce; quercetin and luteolin rhamnosyl-hexosides. Qualitative and quantitative differences were observed between the polyphenol profiles. Caffeic acid derivatives were the main phenolics in green varieties, while flavonols were detected in higher quantities in red varieties and escarole, and anthocyanins were only present in red-leafed varieties. The highest total phenolic content was observed in red-leafed varieties while the highest level of vitamin C was detected in the continental variety. The red varieties showed the highest antioxidant activity by all the methods assayed.     

1-MCP处理对冷藏‘红阳’猕猴桃果实香气成分的影响

探讨1-MCP处理对红阳猕猴桃果实冷藏期间香气成分的影响。以‘红阳’猕猴桃为试材,固相微萃取(SPME)技术为香气富集方法,气相色谱-质谱联用(GC-MS)分析其香气成分。试验共检测出92种香气成分,分属于醇类,醛类,酯类,酮类和烃类等,其中醇类、醛类、酯类和酮类物质数量总体上呈先上升后下降趋势,酮类和醇类香气成分含量先上升后下降,与种类变化趋势一致。1-MCP处理果实酮类香气成分相对含量明显低于对照,醇类物质在贮藏后期高于对照。醛类香气含量在总体上呈上升趋势,与酯类香气含量变化相反,烃类是先降低后升高。表明‘红阳’猕猴桃果实在冷藏过程中香气数量变化与香气含量变化并不是总是相对应的,不同贮藏期对照和处理猕猴桃果实中各类芳香物质的种类和相对含量存在很大差异,1-MCP处理在贮藏过程中抑制了猕猴桃果实酯类香气的产生,并在贮藏后期积累了大量的醇类和醛类香气含量,对果实的整体感官质量有一定的影响。     

Lipids of potato tubers. IV. Effect of growth and storage on the lipid-degrading enzymes of the potato tuber

Six varieties of potato were chosen to investigate the activity of lipolytic acyl hydrolase and lipoxygenase during tuber growth in the field, and subsequent storage at 5 ºC. Apart from an increase in the initial stages of growth, both enzymes displayed relatively consistent levels of activity throughout the life cycle of the tuber. The hydrolase showed an overall slight increase with time and there was a slight decline in lipoxygenase activity during storage. Throughout the physiological stages studied, the activities of both enzymes remained at levels characteristic for a given variety.     

Convenience may increase vegetable intake among young consumers

Current food trends such as healthy eating, plant-based diets and sustainability encourage consumers to eat more vegetables. However, it is a challenge for many, including the younger generations, to meet the dietary recommendations regarding vegetable intake. The purpose of this study was to investigate if vegetable convenience products can increase the daily intake of vegetables among young consumers. A total of 100 participants were randomly allocated to receive either regular or convenience vegetables for a week and filled in questionnaires about vegetable use and consumption before after the intervention. Results showed that participants who received convenience vegetable products significantly increased their daily vegetable consumption by 19% (p = 0.005), but there was no significant difference between the groups during the intervention period. Furthermore, convenience vegetable products were used and perceived differently from regular vegetables. It was found that especially the preparation of the convenient vegetable products had an impact on how the products were perceived. Participants indicated that they were not willing to buy or pay more for convenience in relation to vegetables. In conclusion, convenience vegetable products may increase vegetable intake among young consumers. However, this specific consumer group may find barriers within their values regarding food, consumerism and sustainability, which prevent them from buying convenience food products.     

高原夏菜贮运保鲜技术研究进展

高原夏菜是指生长在高海拔干冷地区的蔬菜,主要填充南方夏季多雨导致的蔬菜市场空缺。目前高原夏菜贮运保鲜体系不完整,标准化产业模式尚未完善,缺乏低耗高效的贮运保鲜技术。因此,需要细分不同种类高原夏菜的贮运保鲜环节,总结相应的生理变化规律,从而形成配套的贮运保鲜技术。本文综述了不同种类高原夏菜贮运保鲜技术研究进展,探究低成本、高效的贮运保鲜技术,分析高原夏菜贮运保鲜中存在的问题,从物理、化学、生物保鲜技术,以及包装、运输方式等方面综述国内外的高原夏菜贮运保鲜技术手段,为高原夏菜不同品种蔬菜的贮运保鲜技术提供理论依据。