Tag Archives: total phenols

xxx D. Kļava, S. Kampuse, L. Tomsone, T. Kince and L. Ozola
Effect of drying technologies on bioactive compounds maintenance in pumpkin by-products
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Effect of drying technologies on bioactive compounds maintenance in pumpkin by-products

D. Kļava, S. Kampuse*, L. Tomsone, T. Kince and L. Ozola

Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Riga street 22, LV-3004 Jelgava, Latvia
*Correspondence: skampuse@inbox.lv

Abstract:

During the pumpkin processing large amounts of waste material as a combination of pumpkin peel, seeds and the flesh between seeds has produced. Therefore it is important to investigate the possibilities for using the pumpkin residues. The aim of this research was to investigate the effect of different drying technologies on maintenance of bioactive compounds in pumpkin by-products. Two pumpkin residue products of Hubard group pumpkins were used to obtain pumpkin powder: residue products formed in the process of extracting industrial pumpkin purée by heating it in a heat exchanger and treating through a sieve of pulpier; residues resulting from pumpkin juice extraction process mechanically pressed from fresh, chopped pumpkins. In order to be able to choose the most suitable drying technology pumpkin by-products were dried in the microwave-vacuum, convective (at 40, 50, 70 and 80 °C) and freeze-drying type dryers. For all samples total carotenes, the ascorbic acid, total phenols content (TPC) and antiradical activity (DPPH˙, ABTS˙+) were determined by using standard methods. The highest total carotenes content was retained in freeze-dried pumpkin powders. The most suitable drying method for obtaining pumpkin powder with the highest ascorbic acid, total phenolic content and antiradical activity is drying in convective type drying at 80 °C temperature.

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1361–1371 Z. Kruma, L. Tomsone, R. Galoburda, E. Straumite, A. Kronberga and M. Åssveen
Total phenols and antioxidant capacity of hull-less barley and hull-less oats
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Total phenols and antioxidant capacity of hull-less barley and hull-less oats

Z. Kruma¹*, L. Tomsone¹, R. Galoburda¹, E. Straumite¹, A. Kronberga² and M. Åssveen³

¹Latvia University of Agriculture, Department of Food Technology, Rigas iela 22, LV-3004 Jelgava, Latvia
²Institute of Agricultural Resources and Economics, Zinatnes iela 2, LV-4126 Priekuli, Latvia
³Norwegian Institute of Bioeconomy Research, Fredrik A. St. Dahls 20, 1432 Ås, Norway
*Correspondence: zanda.kruma@llu.lv

Abstract:

 Grain products are the main source of carbohydrates but they also contain other bioactive substances such as phenolic compounds. Content of phenolic compounds differ among cereal types, varieties, and farming methods. The aim of the current study was to assess total phenolic content and radical scavenging activity in different oats and barley varieties compared to hulled ones. In the experiment hull-less varieties / lines were analysed: three barley (line ‘GN 03386’, from Norway and ‘Kornelija’, ‘Irbe’ from Latvia) and three oats varieties (‘Bikini’, ‘Nudist’, from Norway and ‘Stendes Emilija,’ from Latvia). One hulled variety of barley and oats from each country was included in the experiment for comparison. For the isolation of phenolic compounds ultrasound assisted extraction was used. For all extracts the total phenol content and DPPH, ABTS+ radical scavenging activity were determined spectrophotometrically. Overall, the highest content of total phenols was detected in hull-less barley samples. The barley variety with the highest content was line ‘GN 03386,’ followed by varieties ‘Kornelija’, ‘Irbe,’ and hulled Norwegian barley variety ‘Tyra’. High DPPH and ABTS+ radical scavenging activity was recorded in barley line ‘GN 03386’. Generally, there was strong correlation between total phenol content and ABTS˙+radical scavenging activity and moderate correlation between total phenol content and DPPH radical scavenging activity. In conclusion, the barley varieties had generally higher content of bioactive substances than oats and the barley line ‘GN 03386’ seems to be one of the best.

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929-938 R. Galoburda,, M. Kuka, I. Cakste and D. Klava
The effect of blanching temperature on the quality of microwave-vacuum dried mushroom Cantharellus cibarius
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The effect of blanching temperature on the quality of microwave-vacuum dried mushroom Cantharellus cibarius

R. Galoburda¹,*, M. Kuka², I. Cakste² and D. Klava¹

¹Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, Liela iela 2, LV-3001, Jelgava, Latvia 2Latvia University of Agriculture, Faculty of Food Technology, Department of Chemistry, Liela iela 2, LV-3001, Jelgava, Latvia *Correspondence: ruta.galoburda@llu.lv

Abstract:

The objective of this study was to evaluate the effect of blanching temperature on structure, colour, chemical composition, and rehydration capacity of microwave-vacuum dried chanterelle (Cantharellus cibarius). Fruiting bodies of chanterelle were collected from the forests in Jelgava region of Latvia. Prior to drying, fresh mushrooms were blanched in water at various temperatures of 70, 80, 90 and 100ºC for 3 min, then cooled in water (20ºC). After blanching mushrooms were dried in a microwave-vacuum drier according to the specially designed program. The content of dry matter of chanterelle was 9.5 ± 0.5%. The results revealed that weight loss at 70–90ºC was significantly smaller compared to blanching at 100ºC temperature. The results indicated the tendency of smaller changes in microstructure, weight loss and colour for samples blanched at 70–80°C temperature comparing to the samples unblanched or blanched at higher temperatures. Electrical conductivity in water extract of microwave-vacuum dried chanterelle decreased with increased blanching temperature. Titratable acidity of chanterelle significantly reduced after blanching due to leakage of soluble acids into blanching water.

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