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The effect of heating on degradation of some bioactive compounds (total monomeric anthocyanins, L‐ascorbic acid and total phenolics) and color loss in raspberry pulp were investigated at 60, 70, 80 and 90C for 7 h. Total monomeric anthocyanins and L‐ascorbic acid followed first‐order kinetics, while a zero‐order kinetic model was determined for the degradation of total phenolics. The first‐order reaction was also described for the color loss in terms of Hunter a, b and C values. The activation energies for the degradation of raspberry anthocyanins, L‐ascorbic acid and total phenolics were 49.3, 15.7 and 32.2 kJ/mol, respectively. Higher activation energies (49.0–75.5 kJ/mol) found for color loss indicates, this reaction is more sensitive to the temperature elevations than the other reactions. Practical Applications Raspberries are a good source of bioactive compounds. However, these compounds of raspberries, like many foods, are easily affected by heat treatment. On the other hand, heating is also known as one of the methods of food preservation. So, reaction models are needed for determining the end point of a reaction and kinetic effects during heating. This study showed that how bioactive compounds of a food changed after heating at various temperatures. For this reason, it is supposed that results obtained from this study will highlight to consumers and food processors.

Carob pekmez was stored at 5, 25, 35 and 45°C for studying the reaction kinetics of nonenzymatic browning reactions. Hydroxymethylfurfural (HMF) formation, browning index (A 420 ) and CIE (International Commission on Illumination) colour parameters were analysed to evaluate nonenzymatic browning reactions. HMF formation and A 420 values increased linearly with the storage time and temperature and both followed zero-order reaction. No fitting model was found for the changes in visual CIE parameters. The dependence of rate constant of nonenzymatic reactions on temperature was represented by an Arrhenius equation and the activation values were found as 114.87 kJ mol )1 and 86.62 kJ mol )1 for HMF formation and A 420 values, respectively. The excellent linear correlations (r = 0.728-0.99) among colour parameters, browning index and HMF were found.

Tea is an evergreen plant that enjoys rainy and warm climates, and classified in the Theaceae family. Tea, which is one of the most widely consumed beverages in the world, receives interest due to the flavor and aroma besides beneficial health effects. It is categorized into three major types; not fermented (green and white tea), partially fermented (oolong tea) and fermented (black tea). The objective of this study is to determine physical properties (water activity and color) and chemical properties (antioxidant activity, content of ash, total phenolics, total flavonoids, caffeine and some phenolic compounds) of white, green and black teas. Green tea stands out in terms of bioactive compounds compared to white and black tea. The reason can be explained by nonoxidation of phenolic compounds because of steam treatment to rolled leaves during the production of green tea.

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In this study, it is aimed to determine effect of ultrasonication on some chemical and microbiological properties of sour cherry juice by response surface methodology, since ultrasound is known as an alternative method for thermal food processing. Sour cherry juice was sonicated at varying amplitude levels (50, 75, 100%); moderate temperatures (20, 30, 40 ℃); and treatment times of 2, 6, 10 min at a constant frequency of 20 kHz. Different ultrasonication amplitudes, temperatures, and times had no significant effect on pH,°Bx, and titratable acidity. A significant increase in total monomeric anthocyanins was observed as the amplitude level and temperature increased (p < 0.01). An increase in the total phenolics was also obtained as the temperature increased (p < 0.05). The effect of amplitude level on antioxidant capacity of sour cherry juice was also found significant (p < 0.05). Color parameters (L*, a*, b*, C, h) generally increased by increasing temperature, amplitude level, and treatment time. It was determined that Escherichia coli O157:H7 significantly affected by temperature and treatment time (p < 0.05).