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VİTAMİN C DEGRADATİON OF ROSE HİPS DURİNG DRYİNG AND EFFECTS OF DRYİNG MEDİUM ON VİTAMİN C DEGRADATİON
Abstract
In this study, vitamin C degradation during drying of rose hips was investigated. The degradation of vitamin C was affected by time, temperature and content of moisture. Rate of vitamin C degradation during the drying of whole rose hips was satisfactorily described by a first-order kinetics, and the temperature dependency of the model was described by the Arrhenius relationship. The activation energy and the reaction rate constant were determined as a function of the moisture content. Drying experiments were also conducted on rose hips cut in pieces, and using air-CO2 mixtures. Cutting the rose hips before drying accelerated the drying process and increased the retention of vitamin C. The loss of vitamin C depended on the level of oxygen in the air-CO2 mixture used as a drying medium.
... Raw material drying and processing conditions also significantly affect the level of active compounds in rose hips. However, there are few studies in this area and they mainly relate to ascorbic acid [1,2,10,[31][32][33][34]. ...
... Therefore, it is essential to shorten the process in question to the maximum. However, an increase in drying temperature (from 50 to 60-80 o C) results in the acceleration of the vitamin C degradation [33]. ...
... According to the cited authors, drying of Rosa canina hips at a temperature of 15-20 o C results, depending on the degree of ripening, in even a 2-6-fold drop in ascorbic acid content compared to samples frozen and stored at -70 o C. These adverse changes can be prevented to some extent, since the study of Erentürk and co-authors [32,33] shows that cutting of rose hips shortens air-drying time, thereby preserving more vitamin C. ...
This paper presents the results of a study on the effect of air drying (at a room temperature) and freeze drying on the content of flavonoids, β-carotene and organic acids in to-tal weight of hips (hypanthia and achenes) of roses from the section of Caninae DC. em. Christ. The obtained results show a significant effect of drying conditions on the content of β-carotene and organic acids. In the lyophilized material more organic acids were found, but less β-carotene, than in the rose hips dried at a room temperature. The largest differences were noted in the case of ascorbic acid. Its content in the lyophilizates was on average 5 times higher than in the air-dried hips and it was on average as much as 1.225 g/100 g of dry weight (DW). The amount of citric acid was higher by only 10%, on average. Large differences were also found for β-carotene. Its content in the freeze-dried material, compared to the air-dried rose hips, was on average lower by 74 mg/100 g DW (43%). In the case of flavonoids, the obtained results were ambiguous.
... Przede wszyst-kim stwierdzono w nich znaczne ilości witaminy C. Charakteryzują się również obecnością witaminy A, K, B1, B2, tokoferoli, olejku eterycznego, oleju z dużą ilością nienasyconych kwasów tłuszczowych, aminokwasów, pektyn, garbników, karotenoidów, flawonoidów, antocyjanów, kwasów organicznych i substancji mineralnych. Zawartość witaminy C w owocach róży wynosi od 130 do 6700 mg/100 g [20][21][22][23][24]. Tak wielka różnica wynika z faktu degradacji tego związku, która następuje pod wpływem czasu, temperatury, wody i ilości CO 2 , podczas suszenia, przechowywania i przetwarzania surowca [25][26][27]. Jedną z metod zabezpieczenia poziomu witaminy C w surowcu jest zamrażanie owoców bezpośrednio po zbiorze [28]. Proces ten pozwala na istotne zmniejszenie strat substancji aktywnych: straty witaminy C wynoszą około 5%, pektyn 30-35%, flawonoidów 20-25%, karotenoidów 25-30% i około 50% w przypadku witaminy E i związków steroidowych. ...
The genus Rosa L. consists of approx. 200 wild species distributed in northern hemisphere. Taxonomic relationships within the genus are not very well understood due to the huge variability. The aim of this study is to review genetic and phytochemical research, as well as potential health benefits of rose hip. For ages the roses have been used as a herbal teas, jams or other food products, because they are rich in vitamin C, phenolics and carotenoids. Recent clinical studies have shown that dried rose hips reduced symptoms of
osteoarthritis. Roses still might be a source of new remedies and food supplements.
The stability of reduced and total ascorbic acid in a low moisture dehydrated model food system was determined as a function of water activity, moisture content, oxygen and temperature. Ascorbic acid degradation rates were satisfactorily described by first-order kinetics and were dependent on water activity and temperature. Rate constants obtained for the model system stored with a large excess of oxygen (303 cans) were compared with those reported previously for the case of limited gaseous oxygen (TDT cans). At all conditions of temperature and water activity the degradation of ascorbic acid was greater for the condition of excess oxygen (303 cans). This effect is interpreted as reflecting the consumption of oxygen dissolved in the moisture of the product and the continuous dissolution of excess molecular oxygen present in the 303 cans. The significance of this oxygen effect is further manifested by the change in activation energies for RAA and TAA destruction at 0.1 aw from 7.0 kcal/mole limited oxygen to 10.7 kcal/ mole in excess oxygen conditions. These data suggest that dissolved and gaseous oxygen are primary factors in the storage stability of ascorbic acid in dehydrated food systems.
An accelerated method for determining the kinetic model which describes the loss of ascorbic acid during air drying was developed. The method is based on tests conducted under dynamic conditions, i.e. ascorbic acid loss is studied in the course of the dehydration process during which temperature and moisture content are changing continuously. The results are used to determine the form of the kinetic model and the kinetic parameters relating rate of loss to moisture content, temperature, and reactant concentration. The method successfully predicted the kinetic model describing the loss of ascorbic acid in a simulated air drying process. This approach may eliminate the necessity for time-consuming experiments conducted at each of several combinations of temperature and moisture content and may be applicable to other deteriorative reactions.
ABSTRACTA kinetic model representing ascorbic acid degradation in potatoes as a function of moisture content and temperature was used to find optimal dryer-temperature control paths for minimizing ascorbic acid loss during air drying of potato disks. Optimal dryer-temperature control was also determined for minimizing drying time given a specified minimum retention of ascorbic acid. Constraints were placed on the final moisture content and the air temperature. Optimization was achieved using a simulation-optimization approach based on the complex method.