Avaliação das potencialidades biotecnológicas da semente de goiaba (Psidium guajava L.)

Abstract

Several studies have associated beneficial effects on health to the regular consumption of fruits, vegetables, grains due to the presence of antioxidants in these foods, and so the present study aimed to evaluate the potential of biotech guava seed (Psidium guajava L.), and the main metabolites responsible for its antioxidant activity. Powder from red guava seeds was analyzed, made from the Paluma variety donated by an industry producing frozen fruit pulp. Bakery products were prepared with the substitution of 5 and 10% of wheat flour by guava seed powder, and the acceptability and purchase intent were measured. Analyses of nutritional composition, bioactive compounds, microbiological quality and profile fatty acid of the guava seed powder were carried out. Acetonic, ethanol and methanol extracts were used to quantify the levels of total phenolics, total flavonoids, tannins, to determine the antioxidant activity in different in vitro methods (DPPH, β-carotene / linoleic acid system and Rancimat) and to evaluate the toxicity from Artemia salina sp. The phenolic compounds in ethyl acetate extract were identified and quantified by high performance liquid chromatography (HPLC). The results showed that replacing 5% and 10% of wheat flour in sweet cake and Portuguese flavor pizza dough showed better acceptability and purchase intention, compared to the product without replacements. The chemical and nutritional composition of guava seed powder exhibited varying amounts of macro and micronutrients, with a high concentration of dietary fiber (63.94 g/100 g), protein (11.19 g/100 g), iron (13.8 mg / 100 g), zinc (3.31 mg/100 g) and reduced calorie (182 kcal/100g). Significant amounts of bioactive compounds such as ascorbic acid (87.44 mg/100g), total carotenoids (1.25 mg/100 g), lycopene (182 ± 0.09 μg/100g) and insoluble dietary fiber (63.55 g/100 g) were also found. The lipid profile showed a predominance of unsaturated fatty acid (87.06%), especially linoleic acid (w6) and oleic acid (w9). a microbialogic test showed negative contamination, and no toxicity was found using Artemia salina sp. The acetonic extract showed the highest concentration of phenolic compounds, flavonoids and tannins 49.70 ± 0.48 mgEAG / g; 1.529 ± 0.04 mgEQ / g; 41.159 ± 2.64 mgEAT / g, respectively. The acetonic extract also showed the highest antioxidant powder, in the DPPH assay, IC50 of 4.33 ± 0.08 mg / mL. In the autoxidation of β-caroteno/ linoleic acid system, the ethanol extract (IC50 0.193 ± 0.07 mg / mL) showed antioxidant activity statistically similar to BHT. The Rancimat test, the ethanolic extracts (6.41 ± 0.07 hr) and acetone (6.35 ± 0.00 hr) were able to preserve the oxidative stability of soybean oil for a longer period of time and did not statistically differ from soybean oil added BHT (6.44 ± 0.01 hr). Of the phenolic compounds identified, resveratrol and coumarin presented the highest concentrations, 39.0 ± 0.02 and 48.79 ± 0.02 mg/100g, respectively. Thus, it can be concluded that guava seed powder can be considered an abundant source of antioxidants. Its use would be a feasible alternative to avoid waste and contribute to minimizing the environmental impact, in addition to its incorporation in the food, pharmaceutical and nutraceutical industries.