SUELEN SIQUEIRA DOS SANTOS

Título da Tese: PROCESSO DE EXTRAÇÃO POR ULTRASSOM SEGUIDO DE SECAGEM PARA OBTENÇÃO DE EXTRATOS ANTIOXIDANTES DO RESÍDUO DE AMORA-PRETA (Rubus fruticosus)

Orientadora: Profa. Dra. Grasiele Scaramal Madrona

 Data da Defesa: 02/10/2020

RESUMO GERAL

INTRODUCTION Blackberry (Rubus fruticosus) is a fruit belonging to the Rubus genus and Rosaceae family, known for its high content of bioactive compounds, mainly anthocyanins, that are also responsible for their typical color. The main anthocyanins present in this fruit are cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside, and also contain flavonoids, phenolic acids, and ellagitannins. The fruit processing produces about 20 to 60 % of byproducts, mainly pomace, which is also rich in bioactive compounds that can be recovered by some techniques such as ultrasound-assisted extraction. In addition to extraction, drying methods have also been applied to improve the availability of these products. Among the most used drying methods are lyophilization and spray drying, lyophilization is usually considered an effective way to preserve compounds by using low temperatures, whereas spray drying technology is considered a simple, flexible and economical operation. Obtaining a powder rich in bioactive compounds is of great interest to the food and pharmaceutical industries, however some studies have shown that anthocyanins have low stability to temperature, light, pH, and oxygen. Therefore, the use of maltodextrin as a drying aid agent can improve the stability of these compounds. AIMS The objective of the present study was to evaluate a clean extraction technology followed by two drying methods, in order to obtain blackberry pomace powder as a source of antioxidants, in addition to produce and characterize microspheres with maltodextrin and evaluate the effect of temperature on anthocyanin degradation. MATERIAL AND METHODS A factorial experimental design (22 ) was carried out to evaluate the influence of the presence or absence of ultrasound combined with time in the extraction of bioactive compounds from blackberry pomace. Response parameters included the content of phenolic compounds, anthocyanins, flavonoids, and antioxidant activity. Considering the result of the experimental design, the blackberry pomace (BP) was diluted in water at 500 mg/mL at 60 °C for 45 min using ultrasound-assisted extraction. The obtained extract was subjected to drying by two methods, lyophilization (BL) and spray drying (BS), the identification and quantification of the compounds present in the samples were carried out through analyzes of total monomeric anthocyanins (TMA), total phenolic compounds (TPC), total flavonoids (TF), antioxidant activity by ABTS and DPPH, bioactive compounds quantification by HPLC-DAD, and bioactive compounds identification by ESI-MS and also ATR-FTIR methods. For microsphere production, maltodextrin was used as an auxiliary drying agent, as of the result of the experimental design for extraction, where the blackberry pomace extract (BE) was obtained, maltodextrin was added directly to BE at the ratio of 1:1 (w/w) under mechanical agitation (400 rpm), the sample obtained was identified as BM. Both BE and BM were spray-dried and were evaluated for TMA, TPC, TF, and antioxidant activity by DPPH, ABTS and FRAP methods, color and 8 scanning electron microscopy (SEM). Regarding the effect of temperature and copigmentation, microspheres were subjected to temperatures of 70 °C, 80 °C, 90 °C and 100 °C in a thermostatic bath and evaluated by anthocyanin degradation kinetics. In the experimental design, the analysis of variance (ANOVA) was used to determine the individual linear and interaction regression coefficient using the statistical program STATISTICA version 7.0. Response surface graphs were applied to visualize the simultaneous effect of each variable on each response parameter, the significance of all the terms of the polynomial equation was analyzed statistically (p<0.05). All readings were subjected to statistical analysis using the analysis of variance and Tukey's test with the p-value of

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