Acerola residue extract microencapsules: physical-chemical aspects and bioactive compounds.

Name: Bárbara Teixeira Gomes
Type: MSc dissertation
Publication date: 26/11/2020
Advisor:

Namesort descending Role
POLLYANNA IBRAHIM SILVA Advisor *

Examining board:

Namesort descending Role
ANDRE GUSTAVO VASCONCELOS COSTA Internal Examiner *
JOEL CAMILO SOUZA CARNEIRO Internal Examiner *
MARIA EMÍLIA RODRIGUES VALENTE External Alternate *
PAULO CESAR STRINGHETA External Examiner *
POLLYANNA IBRAHIM SILVA Advisor *
TARCÍSIO LIMA FILHO Internal Alternate *

Summary: The food industries produce large amounts of waste, especially when using fruit as raw material. In most cases, these by-products have no specific destination and are usually underused or disposed of inappropriately, representing a major environmental pollution problem. Pomace, peels and seeds are by-products of the fruit industry, rich in bioactive compounds, and may present higher contents than their respective pulps. It is expected that the present study will encourage the use, new research and value fruit by-products. The objective of this study was to obtain and microencapsulate the residue extract from the pulping of acerola and promote its application in a food model system. The residue extract was obtained by extraction with 80% (v/v) ethanol assisted by bath ultrasound, and showed high concentrations of bioactive, 4646,57 mg of quercetin and 2111,93 mg of p-cumáric acid per liter of extract, high antioxidant capacity and intense red color. The extract was encapsulated by spray dryer (SD) and lyophilization (FD), using as agents maltodextrin (MD), gum arabic (GA) and whey protein isolate (PIS). The powders were characterized in terms of humidity, hygroscopicity, solubility, color, content of phenolic compounds, flavonoids and anthocyanins, antioxidant capacity, efficiency of microencapsulation and morphology. The best powder, defined by the desirability function, was applied in a model gelatin system and the color analysis, total phenolic content, total flavonoids, total anthocyanins, ABTS, DPPH and FRAP antioxidant capacity were performed at zero times, 12, 24, 36 and 48 hours of storage. The spray-dried microparticles exhibited spherical structures with concave and lyophilization presented irregular shape, porous and rough surface. Microencapsulation conditions significantly and differently influence the analyzed variables, so that each condition has advantages and disadvantages. It was observed that the conditions SD/MD and FD/GA were the most advantageous to obtain natural dyes, being that the condition SD/MD presented in general better physical characteristics and the highest content of p-cumaric acid, 170,61 micrograms/gram of powder. The content of phenolic compounds in the powders obtained varied from 1013,88 to 1855,11 mg of gallic acid equivalent/100 g of powder, the content of flavonoids was between 67,95 and 274,31 mg of equivalent catechin/100 g of powder and the total anthocyanins were from 20,19 to 33,85 mg of cyanidin-3-glycoside/100 g of powder. The ABTS and DPPH antioxidant capacity of the powders varied from 21,89 to 85,35 and 19,27 to 66,91 micromol of equivalent Trolox/g of powder, respectively and FRAP of 103,17 to 256,56 micromol of ferrous sulfate equivalent/g of powder. The SD/GA treatment proved effective for obtaining phenolic compounds and flavonoids, with greater antioxidant capacity FRAP and higher concentration of quercetin, 289,38 µg/g of powder. To obtain anthocyanins, the best treatment was FD/GA, with greater antioxidant capacities DPPH and ABTS. The SD/PIS powder was incorporated into gelatin, in which it was found that the bioactive compounds followed the first order degradation kinetics and were sensitive to storage time and to the presence of light. Reductions in antioxidant capacities occurred during storage due to the degradation of phenolic compounds. Gelatine retained its originais color during storage, which is desirable for the future use of this powder in food products. It is concluded that the reuse of acerola residue is a promising and sustainable alternative to be included in food products.

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