Tag Archives: antiradical activity

1442–1450 I. Shepelev, R. Galoburda and T. Rakcejeva
Changes in the total phenol content in the industrial potato peel wastes during the storage
Abstract |
Full text PDF (270 kB)

Changes in the total phenol content in the industrial potato peel wastes during the storage

I. Shepelev*, R. Galoburda and T. Rakcejeva

Latvia University of Agriculture, Faculty of Food Technology, St. Liela 2, LV-3001 Jelgava, Latvia
*Correspondence: igor_shepelev@inbox.lv

Abstract:

 As a zero value by-product from the economic point of view, potato (Solanum tuberosum L.) peel is a good source of phenols. As a manufacturing waste, potato peels are stored at the uncontrolled conditions and are exposed to the fermentative, oxidative, and microbial degradation. The aim of the present study was to determine the phenol degradation dynamics in the stored peels so the maximum storage time could be defined to achieve the efficient phenol extraction. Three different types of samples were prepared by abrasion peeling method and stored at room temperature, in open air, up to six days. Phenol extracts were obtained using ethanol-based solvent. Total phenol content was expressed as a gallic acid equivalent; antiradical activity was measured using the 2,2-diphenyl-1-picrylhydrazylradical. Results revealed that total phenols during the storage are more stable in the larger peel samples that can be stored up to two days without significant changes in the total polyphenol content and antiradical activity. Finely shredded peel demonstrated significant decrease in the total phenol amount and in the antiradical activity already on the second day of the storage. This fact indicated that in the finely shredded peel samples phenols are easily accessible to the oxidative and fermentative processes. It is possible, that after peeling there were big amounts of chlorogenic acid in the samples. When total amount of polyphenols decreased, chlorogenic acid degraded and caffeic acid was released in sufficient amount to hold antiradical activity of the extract on the high level.

Key words:

, ,




969-978 L. Klavina
A study on bryophyte chemical composition–search for new applications
Abstract |
Full text PDF (374 kB)

A study on bryophyte chemical composition–search for new applications

L. Klavina

University of Latvia, Department of Environmental Science, Raina Blvd. 19, Riga, LV-1586, Latvia; e-mail: laura.klavina@lu.lv

Abstract:

Bryophytes are the taxonomic group in the plant kingdom represented with about 25’000 species. They contain a high number of biologically active compounds; however their use as a food source is negligible. The aim of this paper is to evaluate bryophyte chemical composition and new possible applications. In order to evaluate bryophyte potential usage as a raw food material, bryophyte basic chemical content and the secondary metabolite profile was determined. To obtain best results bryophyte secondary metabolite extraction options has been studied. Couple of extraction methods were used (conventional, ultrasound, microwave, supercritical CO2 extraction etc.) and different solvents (ethanol, water etc.). A total concentration of polyphenols and substances determining free radical scavenging activity has been determined. The extracts obtained from bryophytes have remarkable antioxidant activity, the extent of which depends on the extraction conditions and bryophyte species. Comparison of five extraction methods and several solvents indicates that microwave assisted extraction and supercritical CO2 extraction is the most promising approach to obtain highest yields of extractives.

Key words:

, , , ,