ABSTRACT In this study, chemical changes during the development of acerola, cultivar Okinawa, were evaluated. The biochemical alterations during the development of the acerola cultivar Okinawa were evaluated, to determine the peroxidase activity (POD) and its thermal stability. Peroxidase (POD) has been considered the main enzyme responsible for the quality deterioration of fruits. Additionally, characteristics evaluated in this study can be important postharvest quality criteria for fruit processing, screening and breeding. Changes in physiological development were evaluated by the determination of moisture content, ascorbic acid, ashes, total and reducing sugars, pectin, chlorophyll a and b, amounts of anthocyanins, flavonols and total carotenoids. These biochemical determinations may serve as a basis for further improvement of techniques for predicting and modeling the optimal harvesting time. The values of chlorophylls, anthocyanins, flavonols, and carotenoids were higher in the peel rather than in the pulp (p < 0.05). Acerola presents high levels of ascorbic acid. The development of acerola (from opening of flowers to maturation of fruits) was of 25 days. The increase of the values for total and reducing sugars, anthocyanins, carotenoids, the solubilization of pectic acid and degradation of chlorophyll suggested that physiological maturation and harvest day occurred on days 19 and 23 after anthesis, respectively. The specific activity of POD was higher in the green stage. Maximum POD activity was observed at pH 6.5 and 45 ºC. Total inactivation was not achieved, suggesting the presence of isoenzymes with high thermal resistance. A loss of 50% of activity occurred after 4 minutes of treatment at 80 °C.

Abstract The aim of this study was to investigate the effect of acid pretreatment, temperature and enzyme concentration on the acid-enzymatic extraction of soluble collagen from chicken keel bone cartilage. A chemical composition analysis and protein profile characterization of this slaughter by-product were also conducted. The cartilages were extracted with 0.5 mol/L of acetic, lactic and citric acids for 24, 48 and 72 hours. Subsequently, optimization with a 22 factorial design was performed with three replications at the central point for a total of 7 experiments; the analyzed response was the collagen content of the obtained isolates. The cartilage under study has a high protein content (90.27% dry basis) consisting of approximately 35.7% collagen and is a source of essential and predominantly hydrophobic amino acids. Pretreatment with acetic acid for 24 hours led to greater extraction potential and consequently, a better collagen yield (30.12%). The electrophoretic profile of the obtained collagens revealed the existence of an α1 chain, indicating that this collagen was type II. Statistical analysis demonstrated that the acid-enzymatic procedure favored a temperature of 30 °C.

Abstract The spray drying process of a mixed juice of acerola and seriguela was optimized using a 2 4 full factorial design with 16 factorial points and 3 central points. The independent variables were different levels of inlet temperature (110°, 140° and 170 °C), feed flow (0.36, 0.60 and 0.84 L/h), amount of maltodextrin (14-26%) and maltodextrin dextrose equivalent (DE) (5, 10 and 15 DE). The responses were water activity (Aw), moisture content (MC), hygroscopicity (Hyg), powder recovery (PR) and retention of ascorbic acid (RAA). After optimization, an acceptance test and multiple comparison test were performed. Temperature exerted a great influence on Aw, MC and RAA. The optimal drying conditions to obtain acerola and seriguela juice mix powder were an inlet temperature of 140 °C, a flow rate of 0.60 L/h, 20% maltodextrin 10 DE. There was no significant difference in the acceptance of the quality attributes or in the multiple comparison test between the nectars made with the juice mix powder. Acceptance was approximately 70%. Therefore, this acerola and seriguela mix powder can be considered a good source of ascorbic acid and a potential ingredient for the food industry.