Impact of tea leaves types on antioxidant properties and bioaccessibility of kombucha

Five different tea varieties (white, green, oolong, black and pu-erh) were infused, drained and used for kombucha production. Antioxidant capacity, total phenolic content and bioaccessibility values were determined. Extractable, hydrolysable and bioaccessible fractions were used for antioxidant capacity and total phenolic content (TPC) and expressed as µmole TEAC/mL and mg GAE/100 mL, respectively. Antioxidant capacity and TPC were determined by Folin Ciocalteu's, ABTS and CUPRAC methods. In vitro digestion enzymatic extraction was used to determine bioaccessible fractions. It has found that kombucha fermentation with the tea extracts caused to elevate antioxidant capacity, TPC, and bioaccessibility. The green tea kombucha had the highest antioxidant capacity (4153.23 μmole TEAC/mL) and bioaccessibility (50.18%). Therefore, it can be suggested as a good supplement with high nutritional value in kombucha production. In general, TPC content increased significantly. The extractable fractions and bioaccessibility values of the kombucha tea varieties increased due to the fermentation, while the hydrolysable fractions decreased. Antioxidant capacity in the extractable fractions of the green tea kombucha samples was measured to increase by ABTS and CUPRAC methods. Bioaccessibility values of pu-erh tea by ABTS and white tea by CUPRAC were found to increase by the kombucha production.

Technologies and Trends to Improve Table Olive Quality and Safety

Table olives are the most widely consumed fermented food in the Mediterranean countries. Peculiar processing technologies are used to process olives, which are aimed at the debittering of the fruits and improvement of their sensory characteristics, ensuring safety of consumption at the same time. Processors demand for novel techniques to improve industrial performances, while consumers' attention for natural and healthy foods has increased in recent years. From field to table, new techniques have been developed to decrease microbial load of potential spoilage microorganisms, improve fermentation kinetics and ensure safety of consumption of the packed products. This review article depicts current technologies and recent advances in the processing technology of table olives. Attention has been paid on pre processing technologies, some of which are still under-researched, expecially physical techniques, such ad ionizing radiations, ultrasounds and electrolyzed water solutions, which are interesting also to ensure pesticide decontamination. The selections and use of starter cultures have been extensively reviewed, particularly the characterization of Lactic Acid Bacteria and Yeasts to fasten and safely drive the fermentation process. The selection and use of probiotic strains to address the request for functional foods has been reported, along with salt reduction strategies to address health concerns, associated with table olives consumption. In this respect, probiotics enriched table olives and strategies to reduce sodium intake are the main topics discussed. New processing technologies and post packaging interventions to extend the shelf life are illustrated, and main findings in modified atmosphere packaging, high pressure processing and biopreservaton applied to table olive, are reported and discussed.

The impact of drying techniques on phenolic compound, total phenolic content and antioxidant capacity of oat flour tarhana

In this study, the changes in phenolic composition, total phenolic content, and antioxidant capacity of tarhanas supplemented with oat flour (OF) at the levels of 20-100% (w/w) after three drying treatments (sun-, oven-, and microwave drying) were investigated. A total of seventeen phenolic standards have been screened in tarhanas, and the most abundant flavonol and phenolic acid compounds were kaempferol (23.62mg/g) and 3-hydroxy-4-metoxy cinnamic acid (9.60mg/g). The total phenolic content amount gradually increased with the addition of OF to tarhana, but decidedly higher total phenolic content was found in samples oven dried at 55°C as compared with other methods. The microwave- and oven dried tarhana samples showed higher TEACDPPH and TEACABTS values than those dried with the other methods, respectively, in higher OF amounts. Consequently, oven- and microwave-drying can be recommended to retain the highest for phenolic compounds as well as maximal antioxidant capacity in OF supplemented tarhana samples.

Effect of pretreatments on microbial growth and sensory properties of dry-salted olives

The effect of various washing solutions (acetic acid, lactic acid, and chlorine dioxide) and NaCl concentrations (2.5, 5.0, and 10.0%) on the stability of dry-salted olives (cultivars Gemlik and Edincik) during storage was studied. Vacuum-packed olives were stored at 4°C for 7 months and monitored for microbiological changes that occurred in the dry-salted olives during the dry-salting process and for their stability during storage. Microbial populations were enumerated using pour plating (for aerobic plate counts) and spread plating (for counts of lactic acid bacteria and yeasts and molds). Aerobic plate counts were <2.5 log CFU/g for olive samples washed in chlorine dioxide at all NaCl concentrations. At 4°C, the population of yeasts and molds increased steadily during the shelf life in Gemlik olive samples washed with all of the solutions, except chlorine dioxide, whereas yeast and mold counts in Edincik olives decreased depending on the increase in salt concentration. Therefore, different combinations of organic acids, NaCl, and vacuum packaging can be successfully used to control the growth of yeasts and molds in these olives. The combination of vacuum sealing (with a 10-ppm chlorine dioxide wash) and storage at 4°C was the most effective approach for controlling the growth of lactic acid bacteria and yeasts and molds. Members of the sensory panel considered saltiness to be appropriate at 2.5 and 5.0% NaCl. Softness and bitterness scores increased with reduced NaCl concentrations, but rancidity and hardness scores increased as NaCl concentration increased.