Nutritional evaluation, chemical composition and antioxidant activity of some food processing wastes

Abstract EN

This study was carried out to evaluate the chemical composition, nutritional value, bioactive compounds, antioxidant activity and inhibition of lipid peroxidation in linoleic acid system for some food processing wastes and its extracts which were, the peels of pomegranate (Punica granatum L.), two varieties of Egyptian orange (Baladi and Navel) (Citrus sinensis) and pea pod (Pisum sativum).

By using gradient aqueous ethanol (٨٠, ٧٠ and ٥٠% V/V), twelve extracts of the tested wastes were obtained.

Total phenolic contents were measured using Folin-Ciocalteu reagent.

While, total antioxidant capacity of the extracts was estimated by two different methods including: DPPH (١, ١- diphenyl-٢-picrylhydrazyl radical and β-carotene/linoleic bleaching test.

The most important results obtained showed that the highest (P ≤ ٠.٠٥) content of total protein, crude fiber and minerals were found in pea pod.

On the other hand, the highest content of total phenolic compounds detected by HPLC was found in pomegranate peel (٥٤٩٧.٦٧ mg/١٠٠ g dried peels).

While, the highest content of total flavonoids was found in navel and baladi orange peel (٣٩٠٧١.٠٩ and ١٠١٩١.٥٢ mg/kg dried peels, respectively).

In addition, results showed that the highest content of ascorbic acid was found in baladi and navel orange peel (٦٤.٤٩ and ٥٤.٠٤ mg/١٠٠g dry matter; respectively).

The present study indicated that the largest amount of total phenolic content which leads to more effective radical scavenging effect was found in ethanolic extracts (٨٠%) of pomegranate peel (٢٥٩.٣٨ mg GAE/g extract).

Furthermore, percentage of inhibit lipid peroxidation for the different extracts were between ٢٢.٤٦ to ٩٦.٨٤%.

The current results suggest that it should be directed to incorporate powders and extracts of pomegranate peel, orange peel and pea pod into the food processing and preservation technology to improve their nutritional quality and to prolong the shelf-life of these food products.