Caracterização nutricional, tecnológica e funcional de resíduos liofilizados de frutas tropicais

Abstract

The dietary consumption of fruit is linked to beneficial health effects due the presence of fiber, vitamins and bioactive compounds, especially antioxidant phenolic compounds (PC) and vitamins. Brazil has a diversified of tropical fruits production such as acerola, guava and cashew, which are usually processed and transformed into large amounts of agro-industrial pomaces. Thus, this study aimed to characterize freeze-dried acerola pomace (ACE), guava (GUA) and cashew (CAS) in regard to their nutritional, technological and functional aspects, in addition to evaluate the impact of the thermal-treatment. These residues are high in dietary fiber, especially insoluble for GUA (40.6%) and soluble for ACE (14.2%). The GUA residue has higher protein (13.8%) and lipids (9.2%), but overall, all pomaces have reduced caloric content. Minerals such as potassium, calcium and magnesium were found in CAS (K: 83.5 mg/g) and ACE (Ca: 31.9 mg/ g and Mg: 2.8 mg/g). Moreover, all dried residues had low hygroscopicity and satisfactory water (4,4 – 12,0 g/g) and oil holding capacity (3,0 – 5,4 g/g). ACE presented the highest phenolic content (5331.7 mg AGE/ 100g), total flavonoid (760.9 mg CE/ 100g) and antioxidant activity (688.1 μmol TE/g in ORAC) and GUA presented higher proanthocyanidins (217.8 mg PA2/ 100g). ACE also presented outstanding phenolic profile, and salicylic acid (3503.4 mg/ 100g), myricetin (929.4mg / 100g) and catechin (498.2 mg/ 100g) were identified. No antibacterial activity against Salmonella typhimurium, Shigella sonneie, Staphylococcus aureus, Bacillus cereus e Listeria monocytogenes was detected. Severe reduction of total phenolic content was observed for ACE sample, reaching 29% at 150 °C. However, higher antioxidant activity retention (above 70 %) was observed to all pomaces and temperatures. Interestingly, an increased TPC of up to 133% at 150 °C was detected, which may be related to the formation of melanoidins in all pomaces (with variations up to 582%). Based on these results, we conclude that freeze dried pomaces have high nutritional, technological and bioactive potential, and might be used as phytochemical-rich ingredients to different food matrices.