Rapid screening of 420 pesticide residues in fruits and vegetables using ultra high performance liquid chromatography combined with quadrupole-time of flight mass spectrometry

A new method for screening and identification 420 pesticide residues in fruits and vegetables by ultra-performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry(UPLC-Q-TOF/MS)were developed.The samples were extracted with acetonitrile/acetic acid(99:1,V/V),and clean-up by SinChERS-Nano(single-step,cheap,effective,rugged,safe,nano)column,determined by UPLC-Q-TOF/MS.The accurate mass database and MS/MS database which contains 420 pesticides were established,the automatic retrieval of detection results was carried on according to the accurate mass,retention time,isotope ratio,ion fragment information,and so on.Method verification was performed on leeks samples.The results showed that 420 pesticides had good linearity in the range of 0.1-100μg/L,and the correlation coeffificients(R2)was greater than 0.990.The limits of detections(LODs)and limits of quantifications(LOQs)of 420 pesticides were in range of 0.05-2.0 and 0.1-5.0μg/L,respectively.The average spike recoveries at 3 levels were 70.1%to 119.7%,and the relative standard deviations(RSD)were lower than 20%(n=6).With this method,a survey of pesticide residues was conducted for 110 samples of 10 different fruits and vegetables,which provided scientific data for ensuring pesticide residue safety of the fruits and vegetables consumed daily by the public.This method was simple,sensitive and accurate,and could be used for rapid screening of 420 pesticide residues in fruits and vegetables.

Experimental Study and Modeling of a Convective Dryer for Fruits and Vegetables

The present work deals with the study of the thermal performances of a convective dryer for fruits and vegetables. This dryer, operating with energy generated from the combustion of biomass in a boiler connected to a water/air heat exchanger could be a solution to the problematic of energy related to drying. An experimental and theoretical study is carried out on the temperature profile inside the dryer. For this purpose, 10.3 kg of tomatoes were dried on the experimental setup. The operation lasted about 16 hours and reduced the moisture content from 93.8% to 12% in wet basis. The overall thermal efficiency of the convective dryer during the trial is 10.76%. For the theoretical study, the dryer components (boiler, water/air exchanger and drying chamber) are first modeled individually;the different sub-programs are then coupled to form the convective dryer program. The method of global heat balances combined with the one called “ε-NUT” is used. The set of equations is discretized using the implicit method of finite differences, then solved with the Gauss algorithm in Fortran 90. The theoretical results obtained are in good agreement with those measured.

Simultaneous Screening of 733 Pesticide Residues in Fruits and Vegetables by a GC/LC-Q-TOFMS Combination Technique

In this paper,we report the construction of two accurate mass databases and the development of a combination detection method that simultaneously screens for 733 pesticide and chemical contaminant multi-residues via high-throughput liquid chromatography(LC)-and gas chromatography(GC)-quadru pole-time-of-flight mass spectrometry(Q-TOFMS).This work demonstrates that electronic mass spectral standards may replace chemical-source standard materials as references through one sample preparation and the combination of GC/LC-Q-TOFMS screening.This cutting-edge technique has also replaced multiresidue determination using targeted detection with non-targeted screening.The pesticide residue types,sensitivity,recovery,and reproducibility of this combination technique are evaluated in eight fruit and vegetable matrices.This technique shows three advantages:①In comparison with the discovery capability of a single technique,the combination technique shows an improvement of 51.1%(GC-QTOFMS)and 39.6%(LC-Q-TOFMS),respectively;②the combination technique can satisfy a screening limit lower than 10μg·kg^-1 and meet the requirements of“uniform standards,”although some of the pesticide residues could be optimized to further improve screening sensitivity;③over 488 pesticides with recoveries between 60%-120%and relative standard deviation(RSD)<20%at a spiked level of 10μg·kg^-1 were detected with the combination technique in eight different matrices.From 2012 to 2017,this combination technique was applied in an investigation to screen pesticide residues from 1384 sampling locations for 38138 batched samples covering 18 categories and 134 types of fruits and vegetables obtained from across the mainland of China.After statistical analysis,533 pesticides in 115891 determinations were detected,and the regularity of pesticides in the fruits and vegetables sold on the Chinese market was shown.

Fruits and Vegetables Freshness Categorization Using Deep Learning

The nutritional value of perishable food items,such as fruits and vegetables,depends on their freshness levels.The existing approaches solve a binary class problem by classifying a known fruit\vegetable class into fresh or rotten only.We propose an automated fruits and vegetables categorization approach that first recognizes the class of object in an image and then categorizes that fruit or vegetable into one of the three categories:purefresh,medium-fresh,and rotten.We gathered a dataset comprising of 60K images of 11 fruits and vegetables,each is further divided into three categories of freshness,using hand-held cameras.The recognition and categorization of fruits and vegetables are performed through two deep learning models:Visual Geometry Group(VGG-16)and You Only Look Once(YOLO),and their results are compared.VGG-16 classifies fruits and vegetables and categorizes their freshness,while YOLO also localizes them within the image.Furthermore,we have developed an android based application that takes the image of the fruit or vegetable as input and returns its class label and its freshness degree.A comprehensive experimental evaluation of proposed approach demonstrates that the proposed approach can achieve a high accuracy and F1score on gathered FruitVeg Freshness dataset.The dataset is publicly available for further evaluation by the research community.

High Performance Liquid Chromatographic Determination of Phenolic Acids in Fruits and Vegetables

A simple isocratic HPLC technique has been developed for the quantitative analysis of phenolic acids (PAs) in fruits and vegetables. Nine benzoic and cinnamic acid derivatives were separated in less than 30 min, and the resolution was all more than 1.23. The ranges of linearity for PAs standards were 0.2-100 ng, even up to 600 ng (r = 0.983-1.000) and the detection limits were 0.02-0.24 mg/kg. Samples of fresh vegetables and fruits were extracted with 80% mcthanol and ethyl acetate, then purified with C18 Sep-Pak cartridge and determined by HPLC. This method was applied to the determination of PAs in 7 kinds of fruits and vegetables, i.e., apple, pear, Chinese cabbage, cauliflower, turnip, soybean sprout and white grape wine. The content of the 9 PAs varied widely in the 7 kinds ol'foods studied. The average concentrations ofchlorogenic acid in apple (100.2 mg/kg) and pear (30.8 mg/kg) were quite high, and sinapinic acid was remarkable (42.5 mg/kg) in Chinese cabbage, and protocatechuic acid had the highest concentration of all the PAs in white wine.

Effects of bioactive compounds and pharmacological activities in medicinal fruits and vegetables by thermal processing

With the advancement of living standards,the role of healthy diets in maintaining well-being has gained prominence.The concept of“medicinal fruits and vegetables”has attracted much research attention recently.Medicinal fruits and vegetables are rich in nutrients and high in edible value,and are also necessary for people's daily diet.In order to better exert the effect of medicinal fruits and vegetables and prolong their shelf life,this paper reviews the effects of common thermal processing methods(boiling,steaming,microwaving,hot air drying,and pasteurization)on the bioactive compounds and pharmacological activities of medicinal fruits and vegetables.It is found that different heat treatment methods have their own advantages and disadvantages,and microwave drying has greater advantages in comparison.Through the summary of the thermal processing methods of medicinal fruits and vegetables,it is expected to provide a theoretical reference for its rational utilization in the field of fruits and vegetables and the improvement of thermal processing methods.

The role of signal production and transduction in induced resistance of harvested fruits and vegetables

Postharvest diseases are the primary reason causing postharvest loss of fruits and vegetables.Although fungicides show an effective way to control postharvest diseases,the use of fungicides is gradually being restricted due to safety,en vironmental polluti on,and resista nee developme nt in the pathogens.Induced resista nee is a new strategy to control postharvest diseases by eliciti ng immune activity in fruits and vegetables with exogenous physical,chemical,and biological elicitors.After being stimulated by elicitors,fruits and vegetables respond immediately against pathoge ns.This process is actually a conti nuous signal tra nsducti on,in eluding the generati on,transduction,and interact!on of signal molecules.Each step of response can lead to corresponding physiological functi ons,and ultimately induce disease resista nee by upregulating the expressi on of disease resista nee genes and activati ng a variety of metabolic pathways.Signal molecules not only mediate defe nse resp onse alone,but also in teract with other signal tra nsducti on pathways to regulate the disease resista nee resp on se.Among various signal molecules,the sec ond messenger(reactive oxygen species,nitric oxide,calcium ions)and plant hormones(salicylic acid,jasmonic acid,ethylene,and abscisic acid)play an importa nt role in induced resista nee.This article summarizes and reviews the research progress of induced resista nee in recent years,and expounds the role of the above-me ntioned signal molecules in induced resista nee of harvested fruits and vegetables,and prospects for future research.

Power ultrasound for the preservation of postharvest fruits and vegetables

Increasing public demands for improved safety and quality of fruits and vegetables in the fresh market,awaken a growing interest for novel technologies for the preservation of postharvest fruits and vegetables before storage.Ultrasound technology provides one of the methods that with better treating time,enhanced products quality,reduced chemical hazards,low consumption of energy,and is environmentally friendly.This review provides an up-to-date summary of published findings on the application of ultrasound in the preservation of fresh fruits and vegetables.The ultrasound devices commonly utilized,effects of power ultrasound treatment as a factor that affects decay incidence,safety and quality of fresh fruits and vegetables are included.Application challenges and research trends in the future are also analyzed.It is concluded that much progress has been achieved in this field during recent years.These achievements paved the way for the industrial-scale application of ultrasound in the preservation of postharvest fruits and vegetables.

Redox protective potential of fruits and vegetables:A review

Although oxidation reactions are crucial for life,they can also be damaging to cells and tissues,causing variety of chronic ailments like,aging,cancer,autoimmune problems,cardiovascular and neurodegenerative disorders etc.Redox protective systems are present in body for general immunization against free radicals,which can be supported by antioxidants that we take in our daily diet.Natural antioxidants such as flavonoids,hydrolysable tannins,coumarins,xanthones,phenolics,terpenoids,ascorbic acid,carotenoids and proanthocyanins are found in various plant products,including fruits,leaves,seeds oils,and juices.This review gives a brief account of research reports on fruits and vegetables which provide free radical scavenging compounds to the body.

Influence of Probiotic Fermented Fruit and Vegetables on Human Health and the Related Industrial Development Trend

The paper briefly discusses the relationship between chronic diseases and gut health,and points out that an imbalance of intestinal microflora and an inadequate intake of dietary fiber are two important causes of chronic diseases.This paper also summarizes the research status of probiotic fermented fruit and vegetables,and discusses the main achievements of our group in this field and future developments of the related industry.The application of fermentation technology to fruit and vegetable processing and the development of a series of probiotic fermented fruit and vegetable products not only increase the added value of fruit and vegetables,but also organically combine probiotics and their active metabolites with prebiotics(dietary fiber,etc.),thereby promoting intestinal health as well as preventing and relieving chronic diseases.Fermentation technology provides a new approach to the study of the effect of probiotics on human health,and will have a revolutionary influence on probiotic application and on the fruit and vegetable processing industry.Thus,fruit and vegetable fermentation technology has excellent market potential.

Effect of low-temperature plasma on the degradation of omethoate residue and quality of apple and spinach

Dielectric barrier corona discharge was developed to generate low-temperature plasma(LTP) to treat apple and spinach samples contaminated with omethoate. Experimental results showed that,after 20 min exposure, the degradation rate of omethoate residue in apple and spinach was(94.55± 0.01)% and(95.55 ± 0.01)%, respectively. When the treatment time was shorter than 20 min,the contents of moisture, vitamin C and beta-carotene were not affected by LTP. Exploration of related mechanisms suggested that LTP might destroy unsaturated double bonds of omethoate and produce phosphate ion, eventually leading to omethoate destruction. It is concluded that appropriate dosage of LTP can effectively degrade omethoate residue in fruits and vegetables without affecting their quality.

Texture-based latent space disentanglement for enhancement of a training dataset for ANN-based classification of fruit and vegetables

The capability of Convolutional Neural Networks(CNNs)for sparse representation has significant application to complex tasks like Representation Learning(RL).However,labelled datasets of sufficient size for learning this representation are not easily obtainable.The unsupervised learning capability of Variational Autoencoders(VAEs)and Generative Adversarial Networks(GANs)provide a promising solution to this issue through their capacity to learn representations for novel data samples and classification tasks.In this research,a texture-based latent space disentanglement technique is proposed to enhance learning of representations for novel data samples.A comparison is performed among different VAEs and GANs with the proposed approach for synthesis of new data samples.Two different VAE architectures are considered,a single layer dense VAE and a convolution based VAE,to compare the effectiveness of different architectures for learning of the representations.The GANs are selected based on the distance metric for disjoint distribution divergence estimation of complex representation learning tasks.The proposed texture-based disentanglement has been shown to provide a significant improvement for disentangling the process of representation learning by conditioning the random noise and synthesising texture rich images of fruit and vegetables。

Application of plastic containers with RFID in the marketing of fruit and vegetables in Taiwan

This study aims to present a set of operation and management systems for containers used in the transport of fresh agricultural produces.The proposed system utilizes Radio Frequency Identification(RFID)and technologies related to information engineering.An operation and information management system for the marketing of fruit and vegetables using RFID-embedded plastic containers is well planned and developed.In order to promote the use of plastic containers,the study designs an energy-saving and environmentally-friendly container that allows for standardized operation.A related standardized operation flow is tested to fully satisfy the wholesale market demands.The entire flow and operation is also tested by all related sectors of the system.With the application of the RFID tag,real time information generated at the production center can be sent to the wholesale market through a wireless network,thus reducing the labor needed for data input while also reducing human error at the market.This may improve tallying efficiency and reduce costs.

Quail Eggs With Fruit and Vegetables

Ingredients: 15 quail eggs, sliced carrots, fungus, rape or lettuce and cherries. Directions: 1. Boil the quail eggs and peel shells after cooled. 2. Fry the rape. 3. Arrange the peeled quail eggs, carrots slices, fungus and cherries on the plate with the rape.

The membrane lipid metabolism in horticultural products suffering chilling injury

Horticultural commodities suffer chilling injury following exposure to extremely low temperatures,which results in visible symptoms and considerable quality loss.Therefore,it is of significance to understand the mechanism of this physiological disorder and to develop effective strategies to control it.Chilling stress causes alteration in structure and function of the plasma membrane,which is assumed to be the primary event in response to cold stress.During this process,the membrane lipid metabolism plays a pivotal role in membrane fluidity and stability.In this review,we summarized the possible roles of membrane lipid metabolism in the development of chilling injury,having the potential for developing effective strategies to alleviate chilling injury in horticultural products under refrigerated storage in practice.