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Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties

Raspberries are one of Serbia’s best-known and most widely exported fruits. Due to market fluctuation, producers are looking for ways to preserve this fresh product. Drying is a widely accepted method for preserving berries, as is the case with freeze-drying. Hence, the aim was to evaluate convectiv...

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Autores principales: Stamenković, Zoran, Pavkov, Ivan, Radojčin, Milivoj, Tepić Horecki, Aleksandra, Kešelj, Krstan, Bursać Kovačević, Danijela, Putnik, Predrag
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679197/
https://www.ncbi.nlm.nih.gov/pubmed/31336726
http://dx.doi.org/10.3390/foods8070251
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author Stamenković, Zoran
Pavkov, Ivan
Radojčin, Milivoj
Tepić Horecki, Aleksandra
Kešelj, Krstan
Bursać Kovačević, Danijela
Putnik, Predrag
author_facet Stamenković, Zoran
Pavkov, Ivan
Radojčin, Milivoj
Tepić Horecki, Aleksandra
Kešelj, Krstan
Bursać Kovačević, Danijela
Putnik, Predrag
author_sort Stamenković, Zoran
collection PubMed
description Raspberries are one of Serbia’s best-known and most widely exported fruits. Due to market fluctuation, producers are looking for ways to preserve this fresh product. Drying is a widely accepted method for preserving berries, as is the case with freeze-drying. Hence, the aim was to evaluate convective drying as an alternative to freeze-drying due to better accessibility, simplicity, and cost-effectiveness of Polana raspberries and compare it to a freeze-drying. Three factors were in experimental design: air temperature (60, 70, and 80 °C), air velocity (0,5 and 1,5 m [Formula: see text] s(−1)), and state of a product (fresh and frozen). Success of drying was evaluated with several quality criteria: shrinkage (change of volume), color change, shape, content of L-ascorbic acid, total phenolic content, flavonoid content, anthocyanin content, and antioxidant activity. A considerable influence of convective drying on color changes was not observed, as ΔE was low for all samples. It was obvious that fresh raspberries had less physical changes than frozen ones. On average, convective drying reduced L–ascorbic acid content by 80.00–99.99%, but less than 60% for other biologically active compounds as compared to fresh raspberries. Convective dried Polana raspberry may be considered as a viable replacement for freeze-dried raspberries.
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spelling pubmed-66791972019-08-19 Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties Stamenković, Zoran Pavkov, Ivan Radojčin, Milivoj Tepić Horecki, Aleksandra Kešelj, Krstan Bursać Kovačević, Danijela Putnik, Predrag Foods Article Raspberries are one of Serbia’s best-known and most widely exported fruits. Due to market fluctuation, producers are looking for ways to preserve this fresh product. Drying is a widely accepted method for preserving berries, as is the case with freeze-drying. Hence, the aim was to evaluate convective drying as an alternative to freeze-drying due to better accessibility, simplicity, and cost-effectiveness of Polana raspberries and compare it to a freeze-drying. Three factors were in experimental design: air temperature (60, 70, and 80 °C), air velocity (0,5 and 1,5 m [Formula: see text] s(−1)), and state of a product (fresh and frozen). Success of drying was evaluated with several quality criteria: shrinkage (change of volume), color change, shape, content of L-ascorbic acid, total phenolic content, flavonoid content, anthocyanin content, and antioxidant activity. A considerable influence of convective drying on color changes was not observed, as ΔE was low for all samples. It was obvious that fresh raspberries had less physical changes than frozen ones. On average, convective drying reduced L–ascorbic acid content by 80.00–99.99%, but less than 60% for other biologically active compounds as compared to fresh raspberries. Convective dried Polana raspberry may be considered as a viable replacement for freeze-dried raspberries. MDPI 2019-07-11 /pmc/articles/PMC6679197/ /pubmed/31336726 http://dx.doi.org/10.3390/foods8070251 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Stamenković, Zoran
Pavkov, Ivan
Radojčin, Milivoj
Tepić Horecki, Aleksandra
Kešelj, Krstan
Bursać Kovačević, Danijela
Putnik, Predrag
Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties
title Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties
title_full Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties
title_fullStr Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties
title_full_unstemmed Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties
title_short Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties
title_sort convective drying of fresh and frozen raspberries and change of their physical and nutritive properties
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679197/
https://www.ncbi.nlm.nih.gov/pubmed/31336726
http://dx.doi.org/10.3390/foods8070251
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