Characterization of the Red Layer and Pericarp of Processing Tomato using Magnetic Resonance Imaging

Abstract: The characteristics of tomato pericarp are closely associated with peelabililty, an important quality attribute of processing tomatoes. Different types of tissue exist in the pericarp of tomato. The outermost region of the pericarp, the red layer, is removed with the skin during peeling. This study investigated the morphological features and tissue properties of red layer and pericarp for 3 processing tomato cultivars using magnetic resonance imaging (MRI). The red layer can be visualized in MR images with T₂ weighting, indicating the red layer has different properties compared to the rest of the pericarp region. Tomatoes were imaged with a set of MRI sequences with signal intensity dependent on different water proton properties. Principal component analysis (PCA) of the statistical features revealed clustering of fruit by cultivar. The spatial distribution of cultivars in the PCA score plot followed their rank of peeling performance. MRI demonstrated potential as a nondestructive method to characterize tomato pericarp and evaluate the peelability of processing tomatoes. Practical Application: Peelability of tomatoes affects the quality of value‐added whole peel and diced tomato products. The properties of the pericarp of tomato are directly related to the peelability of tomatoes. MRI provided a fast and nondestructive method to characterize the properties of tomato pericarp. The result of this work gives insight into the correlation between tomato pericarp characteristics and peelability.     

CAN WE PREDICT PEELING PERFORMANCE OF PROCESSING TOMATOES?

Tomato processors are increasingly interested in being able to predict whether tomatoes will peel well, and therefore, yield high‐value processed tomatoes. We describe two statistical models for peeling applied to multiple years of data. One model is appropriate for perfect or defect‐free tomatoes, and the second model is valid for the normal population of tomatoes obtained following mechanical harvesting. The ability to peel perfect tomatoes was significantly affected by exposure of tomatoes to temperatures greater than 100F, by fruit weight and by pericarp wall thickness. The peelability of a normal population of tomatoes was influenced by tomato weight and width as well as degree‐days and exposure to temperatures greater than 90F. Thickness of the pericarp walls and red layer positively affected the peelability of normal tomatoes. The ability to predict tomato peelability using statistical models may improve the quality of processed tomatoes and may result in more efficient commercial peeling operations.     

PEELABILITY AND YIELD OF PROCESSING TOMATOES BY STEAM OR LYE

Approximately 25% of the processed tomatoes grown in California are made into value‐added foods such as whole peeled and diced tomatoes. Peel removal is the first step in this process, and it must be optimized for both quality and yield. The effect of peeling conditions on tomato cultivars Halley 3155 and Heinz 8892 (H 8892) was evaluated. Considerable texture loss results from peeling; however, firmness was greater for cv. Halley 3155 than for cv. H 8892 regardless of peeling conditions utilized. Peeling under low steam pressures (12 psig) was insufficient to adequately peel either cultivar. While high pressure steam (18 psig) was more efficient at peel removal, increasing vacuum level from 20 in. to 24 in. did not improve peelability of either cultivar. Because cultivar affected peelability and yield, specific tomato cultivars should be evaluated and directed to either paste or whole peeled and diced tomatoes as appropriate.     

不同去皮方法对番茄去皮效果和品质的影响

为优化现有番茄去皮工艺,开发新的去皮方法,以去皮难易程度和质量损失评价去皮效果,比较手工去皮、热水去皮、碱液去皮、功率超声去皮和超声与碱液联用去皮对去皮效果和产品质地、颜色、番茄红素提取率、p H值和可滴定酸含量等品质的影响,并结合扫描电子显微镜观察不同去皮方法果皮微观结构。结果表明,功率超声去皮较传统的热水去皮和碱液去皮,去皮难度小,质量损失少,且产品品质良好,番茄红素含量较高,而超声与碱液联用去皮较其他去皮方法虽去皮难度小,但质量损失过高。扫描电子显微镜观察结果表明,功率超声去皮较热水去皮、碱液去皮对果皮角质层的破坏力更大,可能是超声的空化效应使果皮与果肉更易分离,从而降低去皮损失。因此,功率超声去皮是一种潜在的新型环境友好型去皮方法。     

DEFECTS AND PEELABILITY OF PROCESSING TOMATOES

Peeling is one of the first operations in the manufacture of whole peeled and diced tomatoes, and the peelability of processing tomatoes is significantly affected by the presence of various tomato defects, in particular yellow eye and blossom‐end rot. Tomato maturity also impacts both the percentage of peeled fruit and yield. Immature fruits are typically undercolored and small in size. Sunburned regions on the tomato surface are difficult to peel as well. In this study, we determined the impact of 24 selected tomato defects on tomato peelability and yield of whole peeled tomatoes. There are potential advantages to sorting to remove selected tomato defects early in the process.     

High-humidity hot air impingement blanching (HHAIB): An emerging technology for tomato peeling

Peeling is an essential operation for tomato processing. A new peeling method, high-humidity hot air impingement blanching (HHAIB) heating technology, was developed as an alternative to the conventional lye and hot-water peeling to eliminate the use of chemicals and the discharge of wastewater. The current work explored the feasibility of HHAIB for tomato peeling. The effects of heating temperature (100–120 °C), relative humidity (20%–40%) and heating time (0–180 s) on the peeling performance were investigated. The optimum treatment was found to be 110 °C heating temperature in combination with 40% of relative humidity and 75 s treatment time, which resulted in lower peeling loss, firmness loss and color deterioration compared with other HHAIB conditions that achieved 100% peelability. The comparative study of optimized HHAIB peeling with conventional lye and hot-water peeling showed that HHAIB peeled tomato obtained lower peeling loss and firmness loss, and higher preservation of phytochemicals, antioxidant capacity and color. In addition, compared with fresh tomatoes, HHAIB processing increased the antioxidant activity, lycopene, and total phenolic content in peeled tomatoes by 16.01%, 10.46%, 12.80%, respectively. The laser scanning confocal microscopy image of fresh tomato skin surface and the scanning electron microscope images of peels and flesh showed that HHAIB caused cracking of the epidermis and melting of the cuticular membrane while reduced the serious damage of flesh.Industrial practicePeeling is a necessary step in tomato processing, which impacts subsequent processing efficiency and product quality. At present, the most common used peeling methods in the industry are hot water or/and alkali peeling, but it induces the loss of water-soluble nutrients, chemical residues and waste liquid treatment. Therefore, the industry urgently needs an alternative peeling technology. The current work shows that HHAIB is a very promising peeling technology as it not only has an excellent peeling performance, but also enhances the preservation of phytochemicals, antioxidant capacity and quality attributes compared to conventional lye and hot-water peeling.     

Mandarin fruit quality: a review

During the last decade, there has been a continuous rise in consumption and global marketing of fresh, easy‐to‐peel mandarins, with current annual production of nearly 29 million tons. Nevertheless, most of the existing knowledge on quality traits of citrus fruit comes from research conducted on oranges and grapefruit, which are the main products for the citrus juice manufacturing industry; relatively little is yet known regarding the unique fruit quality traits of mandarins, nor about the great diversity in these traits among the various natural sub‐groups and varieties of mandarins. In the present review we discuss the physiological, biochemical, and molecular factors governing key fruit quality attributes of mandarins, including fruit colour, size and shape, ease of peeling, seedlessness, flavour, and nutritional quality. Fruit colour, size, and shape contribute to external appearance; peelability and seedlessness to ease of consumption; and flavour and nutritional quality to internal quality. © 2017 Society of Chemical Industry     

USE of ORGANIC SOLVENTS FOR IMPROVING PEELABILITY of TOMATOES

A prepeeling dip was used to demonstrate that removal or modification of the cuticular waxes from the tomato fruit could be used to improve the tomato peeling process. the tomatoes were dipped at various temperatures for I min prior to regular lye peeling. the optimum temperature was found to be 45C. Several organic solvents including chloroform, ethyl acetate, ketones, and alcohols were used. These tomatoes were compared to tomatoes peeled using the lye without the dip. the prepeeling dip reduced the thickness of the cuticular wax layer and produced cracks in the cutin surface. This facilitated good penetration of lye into the tomato resulting in more complete peeling. Peeling after pretreatment produced 86% well peeled tomatoes as compared to 33% well peeled in the control run.     

EVALUATION OF PROCESSING TOMATOES FROM TWO CONSECUTIVE GROWING SEASONS: QUALITY ATTRIBUTES, PEELABILITY AND YIELD

Peelability is an important quality parameter in the selection of tomato cultivars (cvs.) for whole peeled and dice processing. Six processing tomato cvs. were evaluated in two consecutive years to examine the effects of cv., maturity and physical attributes on peelability and yield. Physical attributes of the raw tomatoes (size, weight, pericarp wall thickness, color) and processed paste quality (pH, titratable acidity, soluble solids, Bostwick consistency, serum viscosity, color) were determined. Large variations in physical attributes and paste quality were observed in selected tomato cvs. and maturities. In general, most of the attributes indicative of paste quality were more desirable at the less mature (e.g., pink) stage and declined with maturity. Statistical analysis suggests that there were significant differences in percentage of peeled tomatoes, peel index, and yields of whole peeled and diced tomatoes between two consecutive growing years.     

Genotypic Variation in Tomatoes Affecting Processing and Antioxidant Attributes

Tomatoes are widely consumed either raw or after processing and can provide a significant proportion of the total antioxidants in the diet associated with beneficial health properties. Over the last two or three decades an increasing interest for processing and antioxidant attributes in tomatoes has arisen. The screening of processing attributes of tomatoes is subject of a large number of articles; however, special interest has been addressed to the biochemical composition. The postharvest and industrial processing of tomato in tomato-based products includes several steps. Processing and antioxidant characteristics of the raw fruit are important considering the processing steps and final product. To respond to consumer and industrial complaints, breeders should know the range of genetic variability available in tomato resources, including local genotypes, for improving the mentioned attributes. Characterization and conservation of traditional and modern varieties is a major goal for their preservation and utilization. The bioactive contents have an impact on the processed destines so their stability must be contemplated while selecting the tomato fruits for processing. The endeavor of this review was to examine comprehensively the variation in processing and antioxidant attributes among tomatoes. Role of tomato peel in terms of bioactive contents and information on high pigment (hp) tomato mutants are also touched to some extent. Probably, patterns of variation identified/discussed in this paper would give impetus for planning breeding strategies to develop and improve the new processing cultivars with good antioxidant status.     

Persistence and growth of different Salmonella serovars on pre- and postharvest tomatoes

The interaction of a range of Salmonella serovars with pre- and postharvest tomatoes was evaluated. Serovars were selected on the basis of previous association in tomato-linked outbreaks of salmonellosis (Salmonella Javiana, Salmonella Montevideo, and Salmonella Newport) or those typically isolated from animal or clinical infections (Salmonella Dublin, Salmonella Enteritidis, Salmonella Hadar, Salmonella Infantis, Salmonella Typhimurium, and Salmonella Senftenberg). Salmonella serovars introduced onto the flowers of growing plants were recovered on and within the developing tomato fruit. Of all the Salmonella serovars tested, Montevideo appeared to be more adapted to survival within tomatoes and was recovered from 90% of the fruit screened. All of the Salmonella serovars could persist and grow when introduced onto unripened (green) tomato fruit. In general, growth (internal and external) was promoted at the high incubation temperature (25 degrees C) and high relative humidity (95%), although this was serovar dependent. The growth and persistence of Salmonella introduced on and into ripened (red) tomatoes was serovar dependent. Salmonella serovars Enteritidis, Typhimurium, and Dublin were less adapted to grow in or on intact red tomatoes than were serovars Hadar, Montevideo, or Newport. The results illustrated that a diverse range of Salmonella serovars can become established within and/or on preharvest tomatoes. The majority of Salmonella can grow and become established both on and within unripened tomatoes, but growth on ripened fruit was serovar dependent. The results provide a possible explanation why only a narrow range of Salmonella serovars are associated with foodborne illness outbreaks linked to tomatoes.     

Effects of high pressure and ohmic heating on shell loosening,thermal and structural properties of shrimp (Pandalus borealis)

This study aimed at understanding the effects of high pressure (HP) and ohmic heating (OH) on the peelability, the underlying mechanisms of HP- and OH-induced shell tightening, the thermal and structural properties of shrimp parts. HP improved the peelability of shrimp at low pressure level (<350 MPa) and short holding time (≤3 min) and the optimum condition for peeling was at 100 MPa for 3 min at 5 °C. However, a higher pressure level (>350 MPa) led to a decrease in the peelability. High pressure at 600 MPa stabilized cuticular and epidermal collagen and formed new collagen-like structures by new linkages, which strengthened the muscle-shell connection and reduced the peelability. Shrimp meat induced from HP at 100 MPa and 600 MPa had minorly denatured myofibrillar proteins. OH as a blanching method did not significantly improve the peelability of shrimp at most of the studied conditions. Some extreme conditions (e.g. at 50 °C) caused a markedly low peelability due to occurrence of collagen gelatinization. The gel formation from collagen-gelatin transformation under heating added strength to adherence of shell to epidermis and muscle, as a consequence, a difficult peeling was experienced. OH also denatured proteins in shrimp meat and caused loss of astaxanthin.Industrial relevance.The industrial processing of ready-to-eat shrimp involves the on-ice or in-brine maturation process which loosens the shrimp's shell from its meat, and therefore enable the mechanical peeling. However, the traditional maturation is time consuming (up to several days), inevitably leads to reduced quality of shrimp meat. This study shows the possibility of the application of HP at mild pressure levels to promote the shell loosening at short HP processing time (≤3 min). However, at more severe HP conditions could lead to the shell tightening which was caused by HP-induced stabilization of collagen in shell and epidermis. The study also shows that ohmic heating (<5 min) might not be a significant blanching method to support the maturation since OH had minor positive effect on shell loosening at some OH conditions (e.g. 2 or 10% NaCl, 92 V, and 30 or 35 °C), but had a counter effect at most OH conditions especially at high temperature.     

Numerical Simulation of Variable Water Diffusivity during Drying of Peeled and Unpeeled Tomato

Abstract: A mathematical model was formulated for the estimation, in conjunction with experimental measurements, of water diffusivity parameters during convective drying of peeled and unpeeled tomatoes. Fick's 2nd law of diffusion was solved numerically for a sphere, by explicit finite differences, considering shrinkage effect, variable diffusivity, and constant boundary conditions. Experiments were performed in a laboratory tunnel dryer. The equivalent radius of tomato decreased by 50% until the end of the process, which explains the necessity for shrinkage inclusion in the mass transfer model. The mean estimated diffusivities varied between 2.03 × 10^?10 and 15.1 × 10^?10 m²/s for peeled tomatoes and 0.59 × 10^?10 and 15.2 × 10^?10 m²/s for unpeeled tomatoes. The estimated water diffusivities and their variation with the tested drying temperatures (45, 55, and 65 °C) provide an insight of peeling effect during air‐drying. Peeling was beneficial since yielded greater drying rates and shortened significantly drying times, thus saving energy during drying. In all the studied cases, good agreement was found between experimental and predicted drying curves (≥ 0.99, mean relative deviation [MRD]≤ 0.12, and root mean square error [RMSE]≤ 0.03). In overall, the proposed methodology provides a reliable and easy estimation of temperature and moisture‐dependent mass transfer properties and drying simulation of shrinkable food products such as tomato. Practical Application: Water diffusivity is a food property, difficult in estimation but essential in drying processing optimization. This property was estimated as a function of moisture content and drying temperature employing a numerical simulation procedure. The peeling effect was also studied and found beneficial for lower temperature drying (<55 °C) which is useful in the energy optimization of the drying process as well as the retention of the end‐product quality.     

Enzyme-Assisted Production of Tomato Seed Oil Enriched with Lycopene from Tomato Pomace

Large amounts of a waste known as tomato pomace and consisting mainly of the fruit peel and seeds are generated annually from the industrial processing of tomatoes. This material is rich in lycopene, a phytochemical with antioxidant and chemopreventive properties, and contains many valuable nutrients. In this study, we have investigated the possibility of using the whole waste to produce a lycopene-enriched seed oil. The oil was obtained by cold-pressing the seeds and was subsequently enriched in lycopene (up to 500 ppm) by incorporation of a tomato oleoresin derived from the peels. To increase lycopene recovery, the peels were pretreated with cell-wall-degrading enzymes and solvent extracted. This procedure allowed the production of about 25 kg/ton oleoresin with an average lycopene content of 6.8 wt.%. The compositional characteristics of the oil combined with the production of significant amounts of oleoresin strongly support the use of tomato pomace for producing lycopene-based functional products.     

Changes in pH, acids, sugars and other quality parameters during extended vine holding of ripe processing tomatoes

BACKGROUND: Two important quality attributes of processing tomatoes are pH and titratable acidity. These and other quality attributes can be affected by tomato fruit maturity and over‐maturity. We have determined the magnitude of these maturity effects in four processing tomato cultivars commonly grown in California. RESULTS: Allowing tomatoes to remain on the vine for up to 4 weeks after ripening resulted in an increase in fruit pH of between 0.01 and 0.02 unit per day for the four cultivars examined. The increase in pH was paralleled by a decrease in titratable acidity, due to a loss of citric acid. Glucose and fructose concentrations also declined with increasing maturity after ripening. Other quality parameters (color, lycopene, total pectin, pectin solubility, and Bostwick consistency) all showed little change. CONCLUSION: Vine holding of ripe fruit adversely affects quality, especially pH and titratable acidity. Recent problems with high tomato juice pH encountered by tomato processors in California could be the result of increased average fruit maturity at harvest. Copyright © 2011 Society of Chemical Industry     

Evidence of antiplatelet aggregation effects from the consumption of tomato products,according to EFSA health claim requirements

Abstract

The beneficial effect of fresh tomatoes or processed tomato products on platelet aggregation depends on the presence of bioactive compounds in these products, in sufficient quantities, to produce a relevant physiological effect, when consumed as part of a normal diet. This work is focused on reviewing the development on tomato products bioactive compounds, particularly with reference to its potential biological activity with beneficial effect on the prevention of platelet aggregation.

The most relevant studies found show that all bioactive compounds found in Water-soluble tomato concentrate are in tomato fruit and other tomato products, and there is enough evidence of their beneficial effects. According to the European Food Safety Authority requirements, further intervention studies (human clinical trials) using valid markers should be performed in order to demonstrate the beneficial effects of tomato products as consumer products (paste, puree, sauce or juice) on platelet aggregation. Our PubMed review results support the development of promising nutritional strategies involving tomatoes and tomato products to tackle cardiovascular disease as antiplatelet aggregation.     

猕猴桃碱法去皮工艺参数和效果的决策预报

以陕西中华猕猴桃为植物材料,研究了碱法去皮中NaOH浓度、作用时间和温度三个工艺参数的不同组合对去皮后果实生理指标和效果的影响,结果表明,硬度、可溶性固形物、还原糖、蔗糖、总糖、单宁和总酸的含量均下降,其中以含糖量下降最大。三参数中以NaOH浓度对去皮效果以及果实理化性质的影响最大,其回归方程可预报去皮后果实理化以及感官指标;硬度与各项理化以及感官指标的相关性最好,可作为去皮效果的快速诊断因子。     

The influence of fruit anatomy on ease of peeling of tomatoes for canning

Anatomical features of the outer pericarp region of ripe tomato fruit were correlated with ease of peeling before canning. Fruit of many lines were examined, and were assessed for 11 properties that might be associated with the promotion of peel removal. Highest correlations were found for a steep cell-size gradient towards the outer surface, and also for an absence of small cells in the mesocarp. Several other features were significantly correlated with the ease of peel removal.     

Effect of pre-harvest and post-harvest conditions on the fruit allergenicity: A review

Fruits are an important source of vitamins and antioxidants that can effectively delay aging and contribute to health and well-being of the human kind. However, they are growing to be one of the primary elicitors of food allergies around the world. Fruit allergens can induce an IgE-mediated (Immunoglobulin E) reaction, presenting with a symptom like localized oral allergy syndrome (OAS). Numerous studies showed that varying environmental and cultivation conditions can influence the fruit allergen content during flowering and ripening stages. Further, the variety, harvesting maturity, and storage conditions can also significantly influence the allergenicity potential. For example, unripe apples and tomatoes have lower levels of allergens compared to ripened fruits. Researchers have also reported that modified atmosphere packaging (MAP) can help reduce Mal d 3 content present in apples during storage. Post-harvest processing like peeling is also considered a good method to help reduce the overall allergenicity in few fruits whose peel might contain majority of the allergens. This review will discuss the overall influence of both pre-harvest and post-harvest factors on the fruit allergens. We will also discuss the progress regarding the cause, symptoms and diagnostic methods of fruit based allergies.     

猕猴桃果脯关键生产环节工艺条件的优化

对猕猴桃果脯生产过程中的去皮、护色、干燥等工艺条件进行了研究。结果表明,机械去皮、2.0%喷淋均湿护色、热风+微波干燥新工艺能较好地替代传统加工工艺,并起到缩短加工时间、提高加工效率的作用。