果蔬中外泌体样纳米颗粒的分离、表征和应用研究进展

果蔬中的外泌体样纳米颗粒（exosome-like nanoparticles，ELNs）是由果蔬细胞释放的纳米级囊泡结构，与动物的外泌体具有类似的超微结构，但其脂质、蛋白质及核酸等化学成分具有显著差异，并具有独特的生物学功能。本文综述了2013年以来数十种果蔬中ELNs的相关研究进展，对其提取方法和表征手段进行了分析，重点分析了不同植物来源的ELNs中脂质、蛋白质和核酸类化学成分的组成差异，并对ELNs的潜在生理活性和载体功能进行了探讨，可为果蔬中ELNs的相关研究提供借鉴和启示。     

Dried jujube classification using support vector machine based on fractal parameters and red,green and blue intensity

A new method that combines fractal theory and red, green and blue (RGB) colour intensity was developed to sort dried jujube fruits by using support vector machine (SVM). Our result shows that the new method is fast and accurate in dried jujube fruits classification. The SVM models based on fractal parameters only achieved 85.18–92.73% total accuracy rate. The total classification accuracy of SVM based on RGB intensity values was 94.44%. However, the SVM models based on combining fractal parameters with RGB intensity values achieved 94.44–98.15% total accuracy rate. The best classification accuracy (98.15%) was found when using SVM model based on combining fractal measures (FM) with RGB intensity values (C = 512, γ = 0.0078125). Therefore, the SVM model based on combining FMs with RGB intensity is recommended in dried jujube fruits classification.     

Nonthermal plasma for pesticide and microbial elimination on fruits and vegetables: an overview

Nonthermal plasma (NTP) is defined in terms of partly ionised gas which overall temperature is quite low because the stored energy is mostly in free electrons. Applications of NTP have been expanded to new areas of food applications such as the microbial inactivation and also the elimination of pesticide and toxic chemical residues in food such as fruits and vegetables while nutritional content and key characteristics are still preserved. Plasma treatment has successfully decreased the concentrations of pesticides by about 45‐71%. In this article, NTP technologies as well as investigations about applying of NTP for removing pesticide residues and improving microbial safety in fresh produce are described. Potential applications of NTP in food processing together with some of their challenges and limitations are also discussed.     

Exploring relationships between satiation,perceived satiety and plant-based snack food features

We aimed to identify relations between satiation and subsequent satiety for six plant-based foods (apple, avocado, banana, carrot, chick pea and macadamia) using a panel of ten healthy participants and a complete crossover randomised design. Food was served as a mid-morning snack ad libitum over 20 min until participants were comfortably full, and subsequent satiety was monitored for up to 180 min. Carrot and macadamia had significantly higher perceived fullness during eating, but also significantly lower perceived satiety per gram than other foods. Food energy factors had no strong relationship with perceived fullness, but were significantly positively correlated with satiety. Mastication number had significant effects on both perceived fullness (negative) and satiety (positive). This pilot study showed that plant food factors affecting perceived fullness during eating and subsequent satiety are different, and suggests how portion control through satiation for different plant-based snacks may influence both energy intake and subsequent satiety.     

Multiscale Biomechanics of Tomato Fruits: A Review

Bruising and other mechanical damage to fruit caused by external forces during and postharvesting is manifested at the macroscale but is ultimately the result of failure of cells at the microscale. However, fruits have internal structures and cells from different tissue types react differently to application of an external force. Not much is known about the effects of such forces on single cells within tissues and one reason for this is the lack of multiscale models linking macro- (organ or whole fruit), meso- (tissue), and micro- (cell) mechanics. This review concerns tomato fruits specifically as this is an important crop and is an excellent exemplar of past and proposed research in this field. The first consideration is the multiscale anatomy of tomato fruits that provides the basis for mechanical modeling. The literature on experimental methods for studying multiscale mechanics of fruit is then reviewed, as are recent results from using those methods. Finally, future research directions are discussed, in particular the combination of work over all scales. It is clear that a bottom-up approach incorporating single-cell mechanics in finite element models of whole fruit assumed to have internal structures is a promising way forward for tomato fruits but further method developments may be needed for these and other fruits and vegetables, in particular recovery of representative single cells from tissues for mechanical characterization.     

Optimisation of the peracetic acid washing disinfection of fresh‐cut strawberries based on microbial load reduction and bioactive compounds retention

Total microbial count reduction (TMR), total anthocyanins (TAR), and ascorbic acid retention (AAR) after the operation at different PAA concentrations (0–100 mg L^?1), contact times (10–120 s), and temperatures (4–40°C) were used for multiple optimisation using Derringer′s desirability function. Two optimization scenarios (OP 1 and OP 2) were studied. OP 1 was proposed with the goal to maximize TMR with 90% TAR and AAR; and OP 2 maximizing TAR and AAR with TMR of 2 log UFC g^?1. The optimized variable levels obtained were the following: 100 mg L^?1 PAA, 24 °C and 50 s for OP 1 and 20 mg L^?1 PAA, 18 °C and 52 s for OP 2. Additional validation experiments showed agreement between predicted and experimental results. OP 2 conditions are recommended to fresh‐cut strawberries washing disinfection because of an acceptable TMR, higher TAR and AAR, better sensory attributes, and the economic convenience of lesser PAA consumption.     

Effect of vacuum‐drying,hot air‐drying and freeze‐drying on polyphenols and antioxidant capacity of lemon (Citrus limon) pomace aqueous extracts

The aim of this study was to investigate the effect of freeze‐drying, hot air‐drying and vacuum‐drying at 70, 90 and 110 °C, on dried lemon pomace polyphenols and antioxidant capacity. The total phenolic content and antioxidant capacity were higher in lemon pomace dried by hot air or under vacuum than those dried by freeze‐drying and increased as the temperature increased. The highest total flavonoid content was recorded in the pomace dried under vacuum at 70 and 90 °C. Lemon pomace dried by freeze‐drying had the highest neohesperidin content, whereas pomace dried under vacuum at 70 °C had the highest rutin and p‐coumaric acid content. The highest gallic acid content was recorded in the pomace dried by hot air at 110 °C. The results of this study indicate that drying technique should be carefully selected according to the bioactive compounds aimed to be extracted.     

Changes in the phenolic contents and antioxidant activities of citrus peels from different cultivars after in vitro digestion

The aim of this study was to investigate the effects of in vitro digestion on the phenolic contents and antioxidant activities of citrus peels. Three different varieties of citrus peels (mandarin, ponkan and red tangerine) were treated with simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The results showed that the SGF or SIF treatments of the citrus peels did not significantly increase the total phenolic content (TPC) or total flavonoid content (TFC), except for that of the TFC of ponkan peel treated with SGF. However, simulated in vitro digestion did improve the antioxidant activities measured with FRAP and ABTS methods. The effect of SGF was more positive than those of SIF for the FRAP assay, but the opposite was true for ABTS. Notably, both simulated digestion techniques decreased the DPPH free radical scavenging abilities. Simulated digestion in vitro changed the antioxidant activities of the citrus peels.     

不同贮藏温度对草莓呼吸强度及品质的影响

本文研究了不同贮藏温度(0℃、5℃、10℃、15℃、20℃、25℃、30℃)对草莓呼吸强度、感官评价、失重率、硬度、相对电导率、糖酸比、维生素C和色差的影响。研究表明:贮藏温度越高,草莓呼吸越旺盛,货架寿命越短,草莓30℃条件下的呼吸强度是0℃条件下的13.97倍;草莓在0℃、5℃、10℃、15℃、20℃、25℃、30℃条件下贮藏的商品寿命分别为9 d、7 d、6 d、5 d、3d、2 d、8 h。随着贮藏温度的升高,草莓的失重率、相对电导率和呼吸强度迅速升高,而草莓的感官评价、硬度、糖酸比、维生素C含量、L*、hue值逐渐降低;贮藏在0℃的草莓品质保持最好,贮藏9 d后的感官评价、失重率、硬度、相对电导率、糖酸比、Vc含量、L*和hue值分别为5.4、3.18%、11.13 N、39.05%、12.48、22.01 mg/100 g、37.84、32.81。