Influence of processing on the rheological properties of tomato paste

This paper deals with the influence that some processing variables (sieve pore size and breaking temperature) and tomato variety exert on the linear viscoelastic properties of tomato paste. With this aim, 16 tomato paste samples from four different varieties (with different contents of the pectolytic enzymes polygalacturonase and pectin methylesterase) have been manufactured at different breaking temperatures (65–85 °C) and screen sizes (0.8–2.2 mm). From the experimental results obtained, we conclude that tomato paste behaves as a weak gel, showing a wide plateau region in its linear relaxation spectrum. The linear viscoelastic properties of tomato paste depend dramatically on water‐insoluble solids content and particle size, which may be greatly influenced by processing variables. Nevertheless, the specific action of the above‐mentioned pectolytic enzymes must also be taken into account. © 2002 Society of Chemical Industry     

Non-linear viscoelasticity modeling of tomato paste products

This paper deals with the characterization and modeling of the non-linear rheological properties of tomato paste samples manufactured under different conditions (sieve pore size and breaking temperature). With this aim, flow measurements, dynamic linear viscoelastic and linear and non-linear stress relaxation tests have been carried out on the above-mentioned tomato paste samples. Different geometries with smooth and serrated surfaces have been used to optimize the viscous flow measurements and avoid wall-depletion phenomena. The viscous flow properties of tomato paste samples depend on water insoluble solids (WIS) content and particle size, which may be highly influenced by processing conditions. In general, viscosity follows a power-law relationship with tomato paste water insoluble content and particle diameter. A factorable non-linear viscoelasticity model, the Wagner integral equation, predicts the non-linear rheological response of these products under shear fairly well. The time-dependent part of this model is described by a continuous linear relaxation spectrum, calculated from regularization techniques. The use of the Soskey–Winter damping function provides the best predictions of the viscous flow curves.     

不同品种番茄对发酵番茄酱品质的影响

为了丰富番茄加工品种,开发一种发酵番茄酱。以四种新鲜的番茄品种为原料,添加凯里红酸汤来制作发酵型番茄酱并跟踪发酵过程中总酸、pH值、亚硝酸盐、番茄红素、可溶性固形物含量变化以及对成品感官评价。结果显示：美宝、奥宝番茄感官评价较好,品种间pH值变化无显著差异（P＞0.05）,美宝总酸含量、亚硝峰峰值最高,发酵结束后美宝总酸比市售番茄酱高出34%。美宝、经典欧卡番茄其与市售番茄酱番茄红素含量相近。美宝可溶性固形物含量最高为42%,各品种可溶性固形物含量均大于市售番茄酱。不同品种番茄酱发酵后成分具有一定的差异,结合不同品种的发酵番茄酱之间的特点,美宝番茄发酵后风味比市售番茄酱更佳。     

The impact of industrial processing on health-beneficial tomato microconstituents

The effect of industrial processing was investigated on the stability of tomato carotenoids, phenolic compounds and ascorbic acid. A deep insight in the processed products allowed the quantification of caffeic acid hexosides, which are far more important contributors than the well-known chlorogenic acid, dicaffeoylquinic acids and quercetin oligosaccharides (new feruloyl, sinapoyl and syringoyl derivatives of quercetin apiosylrhamnosylglucoside). (E)-β-Carotene and (E)-lycopene were also quantified along with different mono- and di-(Z)-isomers of lycopene which were tentatively assigned. Processing of fresh tomato into paste had an overall positive effect on the contents in phenolic compounds, no effect on lycopene and a slight and high detrimental effect on β-carotene and ascorbic acid, respectively. The balance between the increase in tomato matrix extractability and microconstituent catabolism was further observed in two contrasted transformations of paste into sauce. Overall, the nutritional quality of tomato-processed products, except for ascorbic acid, is mainly preserved through manufacture.     

The impact of thermal processing on bioactive compounds in Australian native food products (bush tomato and Kakadu plum)

This study was conducted to investigate the effect of food processing on the survival of bioactive compounds in Australian bush food products. The lycopene, beta carotene, and ascorbic acid were detected from bush tomato sauce, bush tomato ketchup and Kakadu plum chilli and ginger sauce. The finished product samples were collected during real food production line at three interval times; beginning, middle and the end of the real time manufacturing processes. The bioactive contents from the three products were stable throughout the heating process. In another experiment, bush tomato sauce (16% dried bush tomato content), Kakadu plum sauce (70% Kakadu plum filtrate) were prepared in the laboratory. Bioactive contents (lycopene and beta carotene) in lab formulated bush tomato sauce increased by 48 and 14% respectively. In contrast, ascorbic acid content in the Kakadu plum sauce lost by 16.9%. The experiment suggested that heat processing increased the level of lycopene and betacarotene but minimised ascorbic acid content in processed Australian Bush food products.     

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.     

Evaluation of in-line absorption photometry to predict consistency of concentrated tomato products

This study evaluated the correlation between optical density as measured by absorption photometry, water-insoluble solids (WIS) and consistency as measured by the Bostwick consistometer for a variety of concentrated tomato products. Linear regression analysis indicated a linear correlation (R²=0.97) between optical density and WIS content in diluted tomato paste, a linear correlation (R²⩾0.92) between optical density and consistency in various commercial tomato products and a linear correlation (R²=0.93) between optical density and consistency during commercial production of tomato puree made from ripe tomatoes. The optical density appeared to be unaffected by product temperature and flow rate. Potential limitations of in-line absorption photometry to monitor and control tomato product consistency are briefly discussed.     

The physico-chemical characteristics of extruded snacks enriched with tomato lycopene

Adding tomato derivatives to traditional starchy extruded snacks can improve their nutritional properties by adding lycopene and fibre; however the physico-chemical properties of these products must also be considered. Ingredients and extrusion parameters, including temperature, alter these properties, but their effect on lycopene content is not known. In this study, crisp low density extruded snacks were manufactured from corn, wheat and rice, with or without dried tomato skin or paste powder extruded at temperatures of 140, 160 or 180 °C. Lycopene content and the physico-chemical properties (expansion, density, hardness, colour parameters and percentage of moisture loss) of the extruded products were measured. Lycopene retention was higher in products containing tomato skin powder and significantly lower when wheat flour was used to make the snacks. Increases in the processing temperature improved the physico-chemical characteristics of the snacks but had no significant effect on lycopene retention (P > 0.05).     

Viscoelastic properties of tomato juice

Tomato is one of the most important vegetables for the food industry. Rheological characterization of tomato products is important for products, equipments and unit operations design and evaluation. It is necessary for process optimization and high quality products assurance. However, the works in literature present variable data, and some rheological characterization, as viscoelastic properties are still scarce. The present work has evaluated the viscoelastic properties of tomato juice, as well as the applicability of the Cox-Merz rule. The obtained data are potentially useful for future studies on food properties and process design.     

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。     

Flavor of tomato and tomato products

Abstract

The characteristic sweet‐sour taste of tomato and its overall flavor intensity are due to the following components: reducing sugars (fructose and glucose), free acids (mainly citric’ acid), their ratio, as well as some volatile substances, not identified so far, and the interplay between the above‐mentioned groups of compounds. Of the minerals, potassium (by influencing the free acid content) and phosphate (due to its buffering capacity) indirectly affect the taste. The effect of the free amino acids (glutamic acid, glutamine, gamma‐aminobutyric acid, and aspartic acid) is not unambiguously proven.

The characteristic tomatolike flavor is predominantly determined by volatile substances. Volatile substances develop partly during ripening, partly during the comminution of the ripe fruit, as an effect of the enzymes activated. Volatile substances characterizing fresh tomato flavor are derived mainly from fatty acids and amino acids. Differences between the flavors of different varieties, the less characteristic, weaker flavor of hothouse‐grown tomatoes or artificially ripened ones, are explained by the different quantitative proportions of the volatile substances. So far no key substance playing a decisive role in the flavor of tomato has been detected. Of the approximately 400 volatile compounds so far identified, several were found, however, which have an important role in the flavor of fresh tomato (cis‐3‐hexenal, trans‐2‐hexenal, 2‐isobutylthiazole, hex‐anal, cis‐3‐hexen‐1‐ol, 2E,4E‐decadienal, 6‐methyl‐5‐hepten‐2‐one, etc.).

In the course of tomato processing the flavor substances undergo substantial qualitative and quantitative change, which may or may not be favorable. Depending on the extent of heat treatment and its duration, the reducing sugar and amino acid content decreases while the acid content (by the formation of pyrrolidone carboxylic acid) increases. A part of the volatile substances (mainly those providing “green” smell) evaporates and at the same time—traceable back to the breakdown of sugars and carotenoids—new components, among them those which characterize the “cooked” smell of tomato products, are formed (e.g., dimethyl sulphide, acetaldehyde). Although our knowledge as to the qualitative and quantitative composition of tomato flavor, the factors affecting it, and the effect of certain compounds on it has substantially increased, we are still not in the position to consciously develop the flavor during cultivation and processing. To achieve this further systematic research work is necessary.     

Color compensation in nitrite-reduced meat batters incorporating paprika or tomato paste

BACKGROUND: Nitrite is a key ingredient the manufacture of meat products, forming a stable pink color characteristic of cured products, retarding the development of rancidity and off‐odors and flavors during storage, and preventing microbial growth. The negative aspects of nitrite and the demands for healthy foods result in the need to reduce nitrite in cured meat products. Paprika or tomato has been employed as natural pigments in meat products. The objective of this work was to determine the effect of incorporating paprika powder or tomato paste on the texture, rancidity and instrumental and sensory color compensation in nitrite‐reduced meat batters. RESULTS: Addition of tomato paste improved moisture content, resulting in harder but less cohesive samples as compared to control and paprika‐containing meat batters. Color characteristics of reduced nitrite samples obtained higher a* red coloration (8.9 for paprika and 7.7–8.0 for tomato paste), as compared to control samples (5.65). Instrumental color was low in control samples, with high values for tomato paste and paprika samples. Nonetheless, tomato paste used to compensate color in nitrite‐reduced meat batters was ranked closer to the control sample in sensory evaluation. CONCLUSION: Color characteristics—instrumental and sensory—in these kinds of meat products were enhanced by the addition of 2.5–3.0% of tomato paste, presenting results close to the non‐reduced nitrite control. Similarly, antioxidant components of tomato paste or paprika reduced lipid oxidation. Nitrite reduction from 150 to 100 ppm could be achieved employing tomato paste as a natural pigment to improve color and texture. Copyright © 2011 Society of Chemical Industry     

Development of a nutritional profile predicting tool for fresh and processed tomato‐based products

This study was aimed at developing a tool to represent the evolution of nutritional profile of food during processing with input data mined from previous published papers or database on composition and reactivity of nutrients, and from minimal experimentations. Tomato‐based products, that is tomato sauce, concentrate and paste, were chosen to evaluate the developed model. The SAIN‐LIM system was used to assess the nutritional profile of the tomato products throughout the process steps, including seven constituents: five basic nutrients (i.e. proteins, fibres, vitamin C, calcium and iron) and two microconstituents found in tomato: β‐carotene and lycopene. The SAIN‐LIM nutritional profiles obtained with this model were compared to that calculated from experimental data. Calculated and experimental nutritional scores showed that process steps involved in tomato‐based products did not affect substantially their nutritional quality. Observed differences were mainly attributed to the kinetic parameter selection and raw product variability. The conclusion offers suggestions to extend the model to other product/process combinations.     

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.     

Chemical characterization of tomato pomace

Tomato‐processing by‐product, also known as tomato pomace, consists of peel and seeds and represents around 4% of the fruit weight. If these wastes remain unused, they not only add to the disposal problem but also aggravate environmental pollution. The aim of this paper is to evaluate the chemical composition of tomato pomace collected at different steps during industrial processing in order to assess the quality of this by‐product. Twenty‐one tomato pomace samples were considered for analysis. Samples corresponded to different steps during tomato processing for paste: seven after pulper, five after finisher, six before turbopress and three after turbopress. Samples were analyzed for moisture content, total and soluble sugars, protein, fat, soluble and total fiber, as well as mineral content. From the results obtained we can conclude that tomato pomace composition (in dry weight basis) is as follows: 59.03% fiber, 25.73% total sugars, 19.27% protein, 7.55% pectins, 5.85% total fat and 3.92% minerals. Copyright © 2006 Society of Chemical Industry     

Rheological Properties of Tomato Paste: Influence of the Addition of Tomato Slurry

ABSTRACT: This article deals with the influence that the addition of tomato slurry into tomato juice exerts on the viscous flow and linear viscoelastic behavior of the final tomato paste. With this aim, 5 tomato paste samples, manufactured at industrial scale, have been studied. Three breaking temperatures and 2 different screen sizes were used to prepare 4 regular tomato paste samples. Moreover, a tomato paste sample with addition of "treated tomato slurry" was manufactured using a breaking temperature of 80 °C and a sieve screen size of 1.2 mm. The results obtained suggest that the addition of treated tomato slurry may be of great interest for tomato paste production.     

Enzyme inactivation of tomato juice by ohmic heating and its effects on physico‐chemical characteristics of concentrated tomato paste

Fresh juice of fully ripe tomato was subjected to ohmic heat (OH) treatment (90°C for 1 min) and the effectiveness of treatment was compared with conventional hot break (CT) treatment (90°C for 5 min). PG (Polygalacturonase) and PME (Pectin methyl esterase) enzyme inactivation achieved by the OH (1 min.) was similar as compared to CT of 5 min. During the kinetic analysis it was observed that the inactivation of PME & PG enzyme and degradation of ascorbic acid followed first order trend in ohmic as well as conventional treatment of tomato juice, however total color change (DE) was found to follow least‐squares non‐linear parameter algorithm behavior. Thermal treatments leads to the increased release of phyto‐chemicals from the matrix which results in a significant (p<0.01) increase in lycopene content during the early phases of the treatments. The Paste (28±0.5 °Brix) obtained after pre‐treatment was analyzed for lycopene, ascorbic acid content and apparent viscosity and color. OH Paste was found more viscous than CT treatment with maximum viscosity of 2.33×103 mPa‐s. The color of OH treated paste was bright red as compared to CT treatment, however the lycopene and ascorbic acid content of paste were found similar in OH and CT. Based on results of present study it is concluded that the ohmic treatment may be applied as an efficient alternative to the conventional method of enzyme inactivation in tomato juice.     

燕麦-玫瑰酱-牦牛酸奶酥制作工艺的优化

目的优化燕麦-玫瑰酱-牦牛酸奶酥的制作工艺。方法以牦牛酸奶作为主要原料,燕麦、玫瑰酱、白砂糖、柠檬酸为试验因素,结合真空冷冻干燥技术制成牦牛酸奶酥。通过单因素试验分析4个因素对产品感官评分和硬度的影响。在此基础上采用响应面法对燕麦-玫瑰酱-牦牛酸奶酥的制作工艺进行优化。结果燕麦-玫瑰酱-牦牛酸奶酥最佳工艺参数为:燕麦添加量24%,白砂糖添加量14%,玫瑰酱添加量7.7%,柠檬酸添加量0.2%,综合感官评分为81.23分,和最佳工艺理论值相近。结论经过优化条件制作的燕麦-玫瑰酱-牦牛酸奶酥呈米黄色或粉色,质地均匀,软硬度适中,具有牦牛酸奶特有的风味和浓郁的燕麦、玫瑰香味,可为相关的产品加工提供理论参考。     

茄汁鲭鱼罐头不脱水工艺条件的优选

生产茄汁鲭鱼罐头取消加热脱水工序是一种新工艺。它有许多优点,但因受各种条件的影响,成品固形物含量难于控制在规定的范围之内。为此,我们以影响固形物含量的四个主要方面作为因素,并各自采用三个水平,利用正交试验优选出两组工艺条件,再从该两组样品中以检验感官质量差异而最后确定的工艺条件为:杀菌时间20′—55′—15′、杀菌温度121℃、盐渍浓度11°Be/3O′及番茄酱浓度24％。当然,后面两个因素和水平无明显影响,可按实际需要合理选定。     

In-Can shelf life of tomato paste as affected by tomato variety and maturity

Summary. An increase in de-tinning activity, and hence a decrease in shelf life, has occurred in South African tomato paste during recent years.
Corrosion rate is shown to be related to the variety of tomato used in the manufacture of paste and to its maturity.
Of the changes in composition associated with these factors, total water-insoluble solids appear to be particularly associated with variations in corrosion rate.