Phytochemical Composition and Antioxidant Capacity of Psidium guajava Fresh Fruits and Flour

Psidium guajava fruits are consumed fresh or processed (beverages, syrup, ice cream, jams and jellies). Guayaba is a fruit highly perishable and susceptible to damage during the postharvest. One strategy to overcome this problem is its processing by using techniques that preserve its organoleptic, nutritive and functional properties and allow getting food with added value. The purpose of this study was to obtain flour from fresh fruits cultivated in Argentina Northwestern by lyophilization and to determine the antioxidant activity and the main phytochemicals present in fresh fruits and flour. Nutritional composition (sugar, protein and fat) and the bioactive phytochemicals (total phenolic compounds, flavonoid phenolic, condensed and hydrolizable tannin, ascorbic acid, pigments such as anthocyanin and carotenoids) as well as fiber content, were evaluated. The flour preserved flavor, aroma and color of pulp from fresh fruits. The flour contained around 30% of sugar, 20% of total protein, 0.5% of fat and high level of crude fiber. Carotenoids and ascorbic acid were the dominant phytochemicals in flour as well as in fresh fruits. The guayaba flour showed antioxidant activity with SC50 values similar to fresh fruits. The flour showed nutraceutical characteristics that are demanded by functional food and could be used as a dietary supplement.

Nutraceutical Properties and Toxicity Studies of Flour Obtained from Capsicum pubescens Fruits and Its Comparison with“Locoto”Commercial Powder

The aim of this research was to evaluate the phytochemical profiles of flour from red, yellow and green fruits of Capsicum pubescens (commun name: locoto) and compare with “locoto” commercial powder (Lcp). Soluble protein (SP), total sugar (TS), free phenolic compounds (FPC), ascorbic acid (AA), total monomeric anthocyanin (TMA), condensed and hydrolizable tannin (CT, HT) and carotenoids (C) were determined by spectrophotometric methods. Multielemental composition by ICP-MS was also done. The flour showed low amounts of calories and high potassium and low sodium levels. Flour from “locoto” fruits contained mainly carotenoids (0.82 to 20 g Eβ-C/100g DW), polyphenolic compounds (681 - 822 mg GAE/100g DW) and ascorbic acid (100 - 199 mg AA/100g DW). The polyphenolic profile of Lcp was similar to flour obtained in our laboratory but the level of carotenoid was lower than that of flour. The fiber content of flour was around 3% in all cases. All preparations obtained from flour and Lcp showed antioxidant activity with SC50 values between 1.4 and 3 μg GAE/mL. Inhibitory capacity on Lipo-oxygenase enzyme was also demonstrated. Non mutagenic effect was detected. The “locoto” flour showed nutraceutical characteristics that are demanded by functional food and could be used as a dietary supplement.