Hydrophilic and lipophilic antioxidant activities of guava fruits.

The objectives of this study were to evaluate the hydrophilic antioxidant activity (AOAH) and the lipophilic antioxidant activity (AOAL); and their correlations with vitamin C, and total phenolic and beta-carotene contents in fresh guava fruits of one white flesh clone ('Allahabad Safeda') and three pink flesh clones ('Fan Retief', 'Ruby Supreme,' and an advanced selection). A ferric reducing antioxidant power assay was used to estimate both AOAH and AOAL from methanol and dichloromethane extracts, respectively. The white flesh clone, 'Allahabad Safeda,' showed higher levels of both AOAH [33.3 microM Trolox equivalents (TE)/g fresh weight (FW)] and AOAL (0.25 microM TE/g FW) than the pink flesh clones that ranged from 15.5 to 30.4 and from 0.12 to 0.13 microM TE/g FW for AOAH and AOAL, respectively. The AOAH was positively correlated with vitamin C (r = 0.92, p < 0.01) and total phenolic (r = 0.97, p < 0.01) but was negatively correlated with beta-carotene (r = -0.73, p = 0.03). The AOAL was not correlated with these antioxidants.

Efecto del escaldado y recubrimiento higroscópico sobre la calidad de zanahorias (Daucus carota var. Chantenay) pre-cortadas durante el almacenamiento / Effect of blanching and hygroscopic coating on quality of fresh cut carrots (Daucus carota var. chantenay) during storage

The effect of blanching at low temperatures (solution 1 acid citric, 50 degrees C for 30 seconds) and the application of glycerol as humectant (3 p/p, 20 seconds) to preserve the quality of fresh-cut carrots (Daucus carota) were studied as individual or combined treatments. Four treatments were evaluated: a control by dipping samples for 30 seconds in distilled water (T1); blanching (T2); glycerol application (T3); and blanching plus glycerol application (T4). Total carotenoids content, color, soluble solids and weight loss were monitored during storage. Results showed no differences between treatments in carotenoids content (p > 0.10) and soluble solids (p > 0.05). However, differences were observed between treatments in weight loss (p < 0.05) and color change (p < 0.05). Blanched samples (T2 and T4) showed small changes in orange color intensity compared to treatments T1 and T3 (p < 0.05).