Dilek Boyacioglu

Changes in antioxidant and metabolite profiles during production of tomato paste.

Tomato products and especially concentrated tomato paste are important sources of antioxidants in the Mediterranean diet. Tomato fruit contain well-known antioxidants such as vitamin C, carotenoids, flavonoids, and hydroxycinnamic acids. The industrial processing of this fruit into tomato paste involves several treatments that potentially affect the final profile of antioxidants and other metabolites in the commercial product. Here we have used both biochemical and metabolomic techniques to assess the effect of each separate step in the industrial production chain starting from fresh fruit to the final tomato paste. Material was collected from five independent tomato paste production events spread over two successive years. Samples comprised the intact ripe fruits and semifinished products after fruit-breaking, separation of the pulp from skin and seeds, evaporation, and finally after canning and pasteurization. The effect of each processing step was determined by different types of analysis. First, the total antioxidant capacity and total phenolic content were determined by commonly used spectrophotometric methods. Second, individual antioxidants in the extracts were identified and compared using an HPLC with online antioxidant detection. Third, in each sample the levels of the major individual antioxidants present, i.e., vitamin C, phenolic compounds (such as rutin and chlorogenic acid), tocopherols, and carotenoids, were quantified. Fourth, an untargeted metabolomic approach using LC-QTOF-MS was used to identify those production steps that have the largest impact on the overall metabolic profile in the final paste as compared to the original fruits. This multifaceted approach has revealed that each processing step induces specific alterations in the metabolic profile, as determined by the different analysis procedures, and that in particular the fruit-breaking step and the removal of seed and skin significantly affect the levels of antioxidants and many other metabolites present in commercial tomato paste.

The Reciprocal Interactions between Polyphenols and Gut Microbiota and Effects on Bioaccessibility

As of late, polyphenols have increasingly interested the scientific community due to their proposed health benefits. Much of this attention has focused on their bioavailability. Polyphenol–gut microbiota interactions should be considered to understand their biological functions. The dichotomy between the biotransformation of polyphenols into their metabolites by gut microbiota and the modulation of gut microbiota composition by polyphenols contributes to positive health outcomes. Although there are many studies on the in vivo bioavailability of polyphenols, the mutual relationship between polyphenols and gut microbiota is not fully understood. This review focuses on the biotransformation of polyphenols by gut microbiota, modulation of gut microbiota by polyphenols, and the effects of these two-way mutual interactions on polyphenol bioavailability, and ultimately, human health.

The effect of industrial food processing on potentially health-beneficial tomato antioxidants.

Increasing desires from both consumers and producers to understand better which nutritive components are present in our food and how these are influenced by industrial processing strategies is resulting in extra research involving the use of state-of-the-art technologies to generate novel biochemical information. In this review, attention has been focused on tomato as this is a product eaten right across the world both as fresh produce and after having been processed in a wide variety of ways. There is a particular interest in tomato as it is a major component in the so-called “Mediterranean diet” which has recently been associated with a healthier lifestyle. Tomatoes are rich sources of a variety of nutritional compounds and especially some key antioxidant components such as the carotenoid lycopene, vitamin C, and a range of polyphenols. The potentially protective properties of these antioxidants are of great interest and the consumer has already become aware of their potential importance. Surveying the literature has revealed that much research has been done on the biochemical composition of tomato and its products. However, it remains difficult to make clear conclusions on optimizing the processing strategy. Many, apparently conflicting, findings have been reported and consequently, in this review, we have drawn attention to these and have attempted to clarify their cause. Finally, a range of recommendations has been made as to how future research might be performed in order to generate more concrete conclusions enabling recommendations towards more optimized processing strategies.

Changes in polyphenol content during production of grape juice concentrate

The production of grape juice concentrate on an industrial scale was evaluated and samples from the main steps of processing have been collected and analyzed. The sampling steps included the selection and washing of grapes (Nevsehir Patlak variety), pressing in order to obtain the juice separate from the seed and the skin fraction, pasteurization, clarification, filtration, evaporation, and filling-packing at 27°C with a Brix of 45°. Samples from each of the processing steps were analyzed by a number of spectrophotometric analyses. A series of anthocyanin compounds was identified using HPLC-MS, and the fate of anthocyanins, quercetin rutinoside and procyanidins was followed using HPLC. The results indicate that the removal of seed and fruit skin removes most of the procyanidins and anthocyanins, while subsequent clarification and filtration treatments further reduce the anthocyanin content.

Home processing of tomatoes (Solanum lycopersicum): effects on in vitro bioaccessibility of total lycopene, phenolics, flavonoids, and antioxidant capacity.

BACKGROUND In order to investigate the effect of home processing on the bioaccessibility of health-related constituents of tomatoes, total lycopene, phenolics, flavonoids and antioxidant capacity were determined from seven different tomato products using an in vitro gastrointestinal digestion model. Additionally, the changes in the contents of the major tomato phenolics were determined and compared for these different tomato products using HPLC. RESULTS The results revealed that paste processing and drying significantly increased the bioaccessible total lycopene content (2.2- and 3.8-fold, respectively), total phenolic content (2.3- and 2.0-fold, respectively), total flavonoid content (9.0- and 2.5-fold, respectively) and total antioxidant capacity (6.3- and 8.0-fold for the DPPH assay, 26- and 33-fold for the CUPRAC assay, respectively) (P < 0.05) compared to fresh tomatoes. HPLC analysis revealed significantly lower (P < 0.05) rutin content in puree and juice. The loss of naringenin chalcone in some tomato products, as well as its conversion into naringenin in heat-treated products was observed. CONCLUSION The current study provided valuable insights into the changes in the content and bioaccessibility of tomato antioxidants as a result of home processing.

A Review on the Effect of Drying on Antioxidant Potential of Fruits and Vegetables

The role of antioxidants in human nutrition has gained increased interest, especially due to their associated health beneficial effects for a number of chronic diseases, including cardiovascular diseases and certain types of cancer. Fruits and vegetables are perishable and difficult to preserve as fresh products. Dried fruits and vegetables can be easily stored, transported at relatively low cost, have reduced packing costs, and their low water content delays microbial spoilage. Air-, freeze-, microwave- and sun-drying are among the most thoroughly studied drying methods. This review provides an overview of recent findings on the effects of different drying techniques on major antioxidants of fruits and vegetables. In particular, changes in ascorbic acid, carotenoids, flavonoids, phenolic acids, total phenolics, and antioxidant activity are discussed in detail.

The effects of juice processing on black mulberry antioxidants

Black mulberry fruit is processed to juice at significant scale in Turkey. The effect of industrial-scale juice production on black mulberry antioxidants was evaluated using samples collected from the main steps of processing; including the selection of fruits, washing, mechanical milling, mashing, cold pressing, pasteurization, and filling-packing. Two major anthocyanins (cyanidin-3-glucoside and cyanidin-3-rutinoside), two phenolic acids (3- and caffeoylquinic acid) and 3 flavonols (rutin, quercetin-3-glucoside, and quercetin-malonyl-glucoside) were identified using LC-QTOF-MS and were quantified using HPLC. Approximately, 60-70% of the fruit anthocyanins were retained in the final juice, which also contained high levels of caffeoylquinic acids, relative to the fruit. Mashing and pressing were the steps which were effective for the recovery of fruit polyphenolics into the juice fraction. Moreover, an in vitro gastrointestinal digestion model, applied to determine the effect of processing on the bioavailability of mulberry antioxidants, indicated a higher anthocyanin bioavailability for the fruit matrix than for the juice matrix.

Investigating the Transport Dynamics of Anthocyanins from Unprocessed Fruit and Processed Fruit Juice from Sour Cherry (Prunus cerasus L.) across Intestinal Epithelial Cells

Anthocyanins can contribute to human health through preventing a variety of diseases. The uptake of these compounds from food and the parameters determining uptake efficiency within the human body are still poorly understood. Here we have employed a Caco-2 cell based system to investigate the transport of key antioxidant food components from sour cherry (Prunus cerasus L.) across the intestinal epithelial barrier. Anthocyanins and (-)-epicatechin were supplied in three contrasting matrices: fruit, processed fruit cherry juice, and polyphenolic fractions obtained by solid-phase extraction. Results show that both compound types behave differently. Fruit or juice matrices display comparable transport across the epithelial cell layer. The juice supplements sucrose and citric acid, which are regularly added to processed foods, have a positive effect on stability and transport. Polyphenolic fractions display a lower transport efficiency, relative to that of the fruit or juice, indicating the importance of food matrix components for intestinal absorption of polyphenols.

Procyanidins in fruit from Sour cherry (Prunus cerasus) differ strongly in chainlength from those in Laurel cherry (Prunus lauracerasus) and Cornelian cherry (Cornus mas)

Sour cherry (Prunus cerasus), Laurel cherry (Prunus lauracerasus), and Cornelian cherry (Cornus mas) fruits are widely used in Turkey, both as food and as traditional medicines. The phytochemical composition and antioxidant capacities of these three cherry types were compared. Fruit flesh was evaluated for procyanidin concentration, subunit composition and degree of polymerization, for anthocyanin composition and for total antioxidant capacity, total phenolic content and total flavonoid content. High concentrations (up to 1 g per 100 g dry weight) of long-chain procyanidins were found in Laurel cherry, whereas concentrations of procyanidins in Cornelian cherry were 25 times lower. Surprisingly, Sour cherry (0.3 g/100 g DW) had a dramatically different procyanidin profile which was dominated by short polymers, with an average chain length of 4 monomer units. This is of particular interest since short-chain procyanidins have recently been suggested to play a role in the prevention of coronary heart disease

Kinetics of non-enzymatic colour development in glucose syrups during storage

Abstract Kinetics of non-enzymatic colour development in glucose syrups after 13 weeks storage at 25, 35, 45 and 55 °C were studied and the shelf lives of syrups under study were estimated. Syrups with two different dextrose equivalents (38 and 59 DE) at three different pH values (4.0, 4.5 and 5.0) were examined. Syrups stored at 25 and 35 °C were not taken into consideration due to minor changes observed during 13 weeks of storage. The longest acceptable shelf life at 55 °C was about 13.9 weeks at pH 4.0 and the shortest, 11.5 weeks at pH 5.O. For syrups stored at 45 °C, the longest shelf life was observed to be 26.2 weeks at pH 4.0 and the shortest 17.3 weeks at pH 5.O. A practical application of these results could be to use the data to estimate the shelf life of glucose syrups with the same composition under any storage temperature.