Use of ultrafiltration for preparing improved tomato pulp

The characteristics of high-quality tomato pulp (commercial def.: crushed or diced tomatoes with about 30% tomato juice as packing medium) canned with tomato juice pulp enriched by ultrafiltration as packing medium were compared with those covered with conventional vacuum-concentrated juice.
Both hot- and cold-break products were prepared and those containing 20% serum-reduced packing juice proved to be the best, showing no signs of syneresis on storage and with improvements in sensory properties, colour and non-enzymatic browning; some volatile components were reduced.     

胡萝卜番茄面包的研制

以胡萝卜和番茄酱为原料,胡萝卜经过适当处理制得高品质胡萝卜汁,将胡萝卜汁和番茄酱在面包生产中加入,通过试验探讨了合适的蔬菜面包产品配方、生产工艺,得出它的最佳配方为胡萝卜汁添加量12%,番茄酱添加量3%,白砂糖用量12%,酵母用量1.4%,水用量45%,开发出营养全面、色泽诱人的胡萝卜番茄面包。     

番茄制汁的工艺条件优化及货架期预测模型的建立

目的优化番茄制汁工艺条件,建立货架期预测模型。方法以红熟且无破损的番茄等外果为主要原料,经去蒂、清洗、热烫去皮、破碎榨汁制成新鲜的番茄汁,研究在不同温度(5、27、37℃)贮藏对产品品质的影响;利用Arrhenius方程为基础,建立相关联动力学模型;研究感官评价、pH、番茄花青素含量、色差在不同储藏时间变化进行番茄汁货架期预测研究。结果 0.03%的黄原胶、0.10%的羧甲基纤维素钠、0.05%的琼脂片组成的复合稳定剂稳定效果最好,口感饱满可口、细腻爽滑,番茄香气清新浓郁。采用模糊权重法对番茄汁货架期间的多项品质指标不同的加权系数进行综合评定。品质综合评价的加权关联度=感官评分sensory×0.25+pH×0.25+番茄红色×0.25+色差×0.25。结论该模型可以用于番茄汁货架期预测。     

番茄汁羊肉糕的研究开发

介绍针对西式肉糕的原辅料和加工过程进行改进后的一种番茄汁羊肉糕的制作工艺流程.对羊肉的搅拌、番茄汁的制作以及番茄汁羊肉糕的烤制等工艺进行研究,开发并制作出一种具有美观外形和独特风味的新型西式番茄汁羊肉糕.     

Changes in pectin methylesterification and accumulation of methanol during production of diced tomatoes

The degree of methylesterification (DM) of the pectins in tomatoes affects the firmness of diced products and the consistency of juices. We examined the changes in DM that occur during commercial production of diced tomatoes packed in tomato juice. Ripe processing tomatoes contained low amounts of free methanol (<20 μg g fresh weight⁻¹) and had a high degree of pectin methylesterification (60%). During production of diced tomatoes, the level of free methanol increased while the degree of pectin methylesterification decreased. Diced tomatoes canned in tomato juice contained about 200 μg methanol g fresh weight⁻¹, and had a DM of about 35% in the dice and less than 25% in the juice. Similar results were obtained for aseptically processed bulk packed tomatoes. Low-temperature blanching of canned diced tomatoes caused additional pectin de-esterification in the diced tomatoes and improved firmness. Heating of the diced tomatoes prior to mixing with topping juice, first to temperatures that maximally activate PME then to temperatures that inactivate PME and other enzymes, is proposed as a way to both improve dice firmness and preserve the consistency of the topping juice.     

响应面优化植物乳杆菌发酵番茄汁工艺及其品质评估

本文以番茄为原料,研发了一款植物乳杆菌发酵饮料.通过单因素及响应面试验确定了番茄汁最佳发酵工艺为发酵温度37℃、菌种接种量2％、发酵时间30 h.结果表明,在发酵过程中番茄汁的pH和总糖含量下降,总酸含量上升,活菌数持续上升后趋于稳定.番茄汁经最佳工艺发酵后,其总酚和总黄酮含量显著上升(P<0.05),ABTS+自由基...     

Behavior of pesticides in tomatoes during commercial and home preparation

Monitoring of pesticide residues in Egyptian tomatoes and its products was studied. The average contents of HCB, lindane, dieldrin, heptachlor epoxide and DDT derivatives were detected at levels 0.009, 0.003, 0.006, 0.008 and 0.083 mg/kg, respectively. On the other hand, the levels of dimethoate, profenofos and pirimiphos-methyl were 0.461, 0.206 and 0.114 mg/kg, respectively. In ketchup and paste samples, most organochlorine and organophosphorus pesticide residues were not detectable. The distribution patterns of pesticide residues within the cuticular and subcuticular tissues in tomatoes were also studied. The skin samples were found to contain the highest levels of HCB, lindane, dieldrin and DDT derivatives. The investigation also indicated that washing with water and/or detergent solution were necessary to decrease the intake of pesticide residues. Freezing, as well as juicing and peeling, were necessary to remove pesticide residues in the skin. Cooking of tomatoes (including processing tomato to paste) helped to eliminate most pesticide residues from contaminated tomatoes. ©     

Processed tomato products as a source of dietary lycopene: bioavailability and antioxidant properties.

Oxidative stress is one of the major contributors to increased risk of chronic diseases. A diet rich in tomatoes and tomato products containing lycopene, a carotenoid antioxidant, has been found to protect against these chronic diseases by mitigating oxidative damage. The study aim was to evaluate the effects of a long-term tomato-rich diet, consisting of various processed tomato products, on bioavailability and antioxidant properties of lycopene. Seventeen healthy human subjects (ten men, seven non-pregnant women) participated in the study. Following a two-week washout period during which subjects avoided foods containing lycopene, all subjects consumed test tomato products including tomato juice, tomato sauce, tomato paste, ketchup, spaghetti sauce, and ready-to-serve tomato soup providing 30 mg of lycopene a day for four weeks. At the end of treatment, serum lycopene level increased significantly (p <0.05), from 181.79 +/- 31.25 to 684.7 +/- 113.91 nmol/L. Similarly, total antioxidant potential increased significantly (p <0.05), from 2.26 +/- 0.015 to 2.38 +/- 0.17 mmol/L Trolox equivalent. Lipid and protein oxidation was reduced significantly (p <0.05). The results suggest that a tomato-rich diet containing different sources of lycopene can increase serum lycopene levels and reduce oxidative stress effectively.     

VISCOSITY AND QUALITY OF TOMATO JUICE AS AFFECTED BY PROCESSING METHODS

ABSTRACT

Quality and viscosity of tomato juice is strongly governed by mechanical and thermal abuse during processing. The effect of processing and storage duration on the viscosity and quality parameters of tomato juice was evaluated in the present work. Tomato juice was obtained by two different methods, normal method (NM) and variable method (VM), and was heated by both conventional and microwave hot break treatments. Tomato juice was evaluated for various quality characteristics including precipitate weight ratio, degree of serum separation (DOSS), Brookfield viscosity, lycopene levels, vitamin C, phenols and antioxidant activity. Changes observed in several quality parameters during storage were statistically insignificant. The methods and processing had the greatest contribution toward viscosity, whereas storage duration had no significant effects. Viscosity parameters viz precipitate weight, DOSS and Bostwick consistency revealed that juice processed by VM was more viscous than that of NM, irrespective of the hot break processing used. Ascorbic acid and lycopene content varied significantly with mechanical methods and processing conditions. However, phenolic content and antioxidant activity remained stable. The variable process represents an improvement over the conventional by enabling tomato processors to improve the consistency of the tomato product.

PRACTICAL APPLICATIONS

Quartering or slicing tomatoes followed by hot break processing techniques can significantly improve the quality of tomato juice in terms of reduced degree of serum separation and precipitate weight ratio. The modified technology could be considered as a viable and economical method for small‐ and medium‐scale tomato processors with limited resources and facilities at their disposal.

     

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     

A multi-enzyme bioelectrode for the rapid determination of total lactate concentration in tomatoes,tomato juice and tomato paste

This work presents a new multi-enzyme bioelectrode for the combined determination of d(−)-l(+)-lactic acid in samples of whole tomatoes, chopped tomatoes, tomato paste and tomato juice. The principle of the biosensor is based on the catalytic activity of the enzymes l(+)-lactic acid oxidase (LOD), d(−)-lactic acid dehydrogenase (D-LDH) and horseradish peroxidase (HPO). The three enzymes are immobilized on the tip of an amperometric oxygen selective electrode. The total concentration of d(−)-l(+)-lactic acid is proportional to the amount of O₂ consumed. The biosensor has been tested for standard solutions of d(−)-l(+)-lactic acid, as well as for real samples. The latter set of experiments has been carried out in three different laboratories, indicating a good repeatability and reproducibility of the obtained results. The main characteristics of the lactate biosensor on real samples (whole tomatoes, chopped tomatoes, tomato paste and tomato juice) have been compared, in terms of both analytical and practical features, with those of a traditionally employed enzymatic-spectrometric technique, based on the oxidation of d-l-lactic acid, catalysed by d-lactate dehydrogenase and l-lactate dehydrogenase, with production of pyruvate and NADH, and on the subsequent spectrometric determination, at λ= 340 nm, of the NADH formed.     

Contribution of some volatile tomato components and their mixtures to fresh tomato aroma

Some volatile components of fresh tomatoes and mixtures of these components were evaluated for their contribution to fresh tomato aroma. cis-Hex-3-enal was the only individual component evaluated which was rated moderately similar to the aroma of fresh tomatoes. A mixture of cis-hex-3-enal, 2-methylhept-2-en-6-one, eugenol and β-ionone significantly improved the aroma of tomato juice prepared from foam-mat-dried tomato powder. Since the individual components of the mixture did not give significant improvement, the desired effect probably occurred as a result of a complex interaction among the added components and juice.     

Stability of carotenoids in tomato juice during processing

The stability of carotenoids in tomato juice as affected by various processing treatments was studied. Fresh tomatoes were crushed, hot-broken at 82 °C, screened and the juice was subjected to the following treatments: (1) heated at 90 °C for 5 min prior to canning; (2) heated in water at 100°C for 30 min after canning; (3) heated at 121°C for 40 s before canning (high-temperature-short-time treatment). The results showed that 16 carotenoids, including all-trans plus cis forms of lutein, lycopene and -carotene, were present in tomato juice. Most cis isomers of carotenoids showed inconsistent change during heating. The high-temperature-short-time treatment generated the highest yield of all-trans plus cis forms of lutein and lycopene, followed by heating at 90 °C for 5 min and heating in water at 100 °C for 30 min. Only a minor change in -carotene was observed for these heating treatments.     

IN-LINE MONITORING OF TOMATO CONCENTRATE PHYSICAL PROPERTIES DURING EVAPORATION

This work continues the development of an ultrasonic sensor system for in‐line measurement of the physical properties of fluid foods. The test system was a semi‐batch evaporator in which juice from three varieties of processing tomatoes was concentrated from 5 to 24 Brix. The physical properties of the tomato concentrates were measured and correlated to ultrasound properties. Speed of sound was linearly correlated with density, soluble solids content and total solids content of the tomato concentrates. Shear viscosity of the tomato concentrates flowing in viscometric pipe flow was evaluated using ultrasonic Doppler velocimetry (UDV). The UDV technique combines a fluid velocity profile and a simultaneous pressure drop to create a rheogram. Simple shear viscosity was modeled as power law behavior for tomato concentrates as a function of solids content for the three processing varieties. Off‐line measurements of apparent viscosity were well correlated to the in‐line measurements.     

番茄调味酱的工艺配方优化

本文在分析不同工艺制备的番茄原浆品质优劣基础上,系统研究了白砂糖、酿造食醋、食盐、变性淀粉对番茄调味酱品质的影响,并采用正交试验方法对番茄调味酱的制备工艺进行优化,以期获得高品质的番茄调味酱产品。研究结果表明,本研究优化获得的番茄调味酱最佳工艺配方为:将超冷破原浆番茄酱25 g、热破原浆番酱25 g、白砂糖8 g、酿造食醋5 g、食盐3 g、变性淀粉3 g、水33 g调配混合,经过高温杀菌灌装而制得番茄调味酱。通过与市售5款番茄调味酱感官评价比较,发现本试验组制备的番茄调味酱感官得分最高(92.2分),表明采用本实验配方制备的番茄调味酱在感官品质上具有一定市场竞争力、能满足消费者口感要求。     

Qualitative and nutritional differences in processing tomatoes grown under commercial organic and conventional production systems

ABSTRACT:  Organically grown products experienced a doubling in percent penetration of organic sales into retail markets during the period from 1997 to 2003; however, there is still a debate over the perceived quality advantage of organically grown fruits and vegetables. In a study focusing on commercial production of processing tomatoes, samples were analyzed from 4 growers with matched organic and conventional fields. For the 4 growers studied, individual analysis of variance results indicated that tomato juice prepared from organically produced tomatoes on some farms was significantly higher in soluble solids (°Brix), higher in consistency, and titratable acidity, but lower in red color, ascorbic acid, and total phenolics content in the microwaved juice. Results were significantly different among specific growers, and this may be attributed to differences in soil type and soil nutrients, tomato cultivar, environmental conditions, or other production-related factors. Higher levels of soluble solids, titratable acidity, and consistency are desirable for the production of tomato paste, in that tomatoes with these attributes may be more flavorful and require less thermal treatment. This has the potential to result both in cost savings from less energy required in paste manufacture and potentially a higher quality product due to less thermal degradation of color, flavor, and nutrients. Future work may involve a larger number of commercial growers and correlation to controlled university research plots.     

食品加工企业的会计核算与监督研究分析

目的分析不同会计核算方式对食品加工企业利润的影响。方法以番茄加工企业A企业为例,分别采取不合栺原材料成本计入原材料采购成本的会计核算方法和不合栺原材料成本不计入原材料采购成本的会计核算方法,对A企业购买的800 kg番茄迚行会计核算,分析不同核算方式对A企业成本和利润的影响。结果不合栺原材料的成本是否计入原材料采购成本对番茄酱生产成品的总成本和单位成本都会产生影响。2种不同的会计核算方式对企业总利润的影响是相同的,但是对企业单月销售的利润影响会出现较大的差别。利用不合栺原材料的成本计入原材料采购成本的方式能够使企业获得更大的利润。结论本研究为食品加工企业选择合适的会计核算方法提供理论参考。     

Proteolytic fungi isolated from decayed and damaged raw tomatoes and implications associated with changes in pericarp pH favorable for survival and growth of foodborne pathogens

Raw and minimally processed high-acid fruits and vegetables are considered to be at low or no risk for supporting growth of foodborne pathogens. The potential increase in the pH of tissues as a result of fungal growth, however, may enhance the potential for survival and growth. We examined 77 decayed and 138 damaged, raw, ripe tomatoes for the presence of yeasts and molds that produce proteolytic enzymes and other metabolites that can potentially increase the pH of pulp tissue. The pH of decayed and sound radial pericarp tissues (pulp) of decayed tomatoes ranged from 4.7 to 7.8 (mean = 6.2) and 4.3 to 5.8 (mean = 5.0), respectively, whereas the pH of damaged and sound pericarp of damaged tomatoes ranged from 4.2 to 7.8 (mean = 5.2) and 4.2 to 8.0 (mean = 4.9), respectively. The pH of sound pericarp of 8.5% of decayed tomatoes and 3.4% of damaged tomatoes, respectively, was > 5.41. In contrast, the pH of 70% of the decayed tissue and 18% of the damaged tissue was > 5.41. Fungal isolates (n = 371) recovered from decayed and damaged tomatoes on dichloran rose bengal chloramphenicol agar were examined for proteolytic activity on gelatin agar and standard methods caseinate agar. One hundred eight (29%) of the isolates exhibited proteolytic activity on one or both differential media; 96 (89%) were molds, and 12 (11%) were yeasts. The pH of both media increased at the edge of proteolytic fungal colonies. Growth of proteolytic isolates from decayed tomatoes on tomato juice agar (pH = 4.3) and on the surface of tomato juice (pH = 4.1) caused an increase in mean pH values at the colony/medium interface to 7.2 and 6.4, respectively. Results show that some fungi capable of infecting raw tomatoes, as well as the mycoflora incident on tomato surfaces, can increase the pH of pericarp and juice to levels favorable for growth of most foodborne pathogenic bacteria.     

Ph AND ACIDIC STABILITY DURING STORAGE OF ACIDIFIED AND NONACIDIFIED CANNED TOMATOES

A study was conducted to evaluate pH stability of acidified tomato packs during storage for 1 yr at 24°C, to associate pH stability with tomato composition, and to determine the variability of pH within the canned product caused by tomato cell walls and other structural matter. Results show that pH of acidified tomatoes is as stable during heat processing and storage as that of nonacidified tomatoes.     

Detection of the sour-rot pathogen Geotrichum candidum in tomato fruit and juice by using a highly specific monoclonal antibody-based ELISA

Geotrichum candidum is a common soil-borne fungus that causes sour-rot of tomatoes, citrus fruits and vegetables, and is a major contaminant on tomato processing equipment. The aim of this work was to produce a monoclonal antibody and diagnostic assay for its detection in tomato fruit and juice. Using hybridoma technology, a cell line (FE10) was generated that produced a monoclonal antibody belonging to the immunoglobulin class M (IgM) that was specific to G. candidum and the closely related teleomorphic species Galactomyces geotrichum and anamorphic species Geotrichum europaeum and Geotrichum pseudocandidum in the G. geotrichum/G. candidum complex. The MAb did not cross-react with a wide range of unrelated fungi, including some likely to be encountered during crop production and processing. The MAb binds to an immunodominant high molecular mass (> 200 kDa) extracellular polysaccharide antigen that is present on the surface of arthroconidia and hyphae of G. candidum. The MAb was used in a highly specific enzyme-linked immunosorbent assay (ELISA) to accurately detect the fungus in infected tomato fruit and juice. Specificity of the ELISA was confirmed by sequencing of the internally transcribed spacer (ITS) 1-5.8S-ITS2 rRNA-encoding regions of fungi isolated from naturally-infected tomatoes.