Effects of drying and pretreatment on the nutritional and functional quality of raisins

Abstract

Table 1. Mean values of water activity and main compounds in the Thompson 2 seedless grape variety before and after each drying treatment. In parenthesis is the 3 standard deviation. 4 5 Table 2. Mean values of water activity and main compounds in the Imperial 6Seedless variety before and after each drying treatment. In parenthesis is the 7 standard deviation. 8 9 Table 3. Mean values of water activity and main compounds (referred to fresh 10 fruit mass) of the two varieties of grapes dried by the two drying treatments. In 11 parenthesis is the standard deviation. 6 Abstract: 7The close relationship between the consumption of fruits and health status stems from 8 the nutritional and non-nutritional compounds found in fruits which play a key role in 9 the prevention of different diseases. However, fruit processing and storage greatly affect 10 fruit compounds. The aim of the present work was to study the influence of processing 11 on the stability of macro and micronutrients present in grapes, with a view to 12 recommending products that provide the highest nutritional quality and the best health 13 conditions. The study focused on fruit dehydration treatments. Conventional and 14 microwave-assisted air-drying processes were used to obtain raisins. Dehydration 15 caused a decrease of all grape compounds studied excluding total phenols. Moreover, 16 compared to conventional processing, microwave-assisted drying produced greater 17 losses of ascorbic acid in the grape and increased pectin solubilization with a 18 consequent change in texture. However the microwave-dehydrated samples showed 19 higher antioxidant activity. 20 21

Total phenolics, antioxidant capacity, colour and drying characteristics of date fruit dried with different methods

“…The effects of drying treatments on the phenolic compounds of foods have been studied before. Some previous studies showed that heat treatment is very effective for increasing the total phenolic content in different foods, such as dried apricots (Sultana et al, 2012), tomatoes (Chang et al, 2006) and raisins (Carranza-Concha et al, 2012). Although some authors (Zanoelo et al, 2006;Sultana et al, 2012) note that total phenolics decrease during thermal processing of foods, others (Dewanto et al, 2002) have reported no significant changes.…”

Influence of different drying techniques on drying parameters of mango

“…The influences of drying techniques on the phenolic compounds of foods were inspected before. Some of these studies had shown that heat treatment is very practical for raising the TPC in various food samples such as dry raisins (Carranza-Concha et al, 2012), apricots (Sultana et al, 2012) and orange peels (Chen et al, 2011). Additionally, some results pointed that microwave technique raised the TPC considerably in pepper, broccoli, green beans (Turkmen et al, 2005) and barley (Gallegos-Infante et al, 2010).…”

Avaliação Da Manutenção Da Qualidade De Uvas Passa BRS Vitória Após Aplicação De Pré-Tratamento Químico

“…Diferentes tipos de pré-tratamento químico são utilizados para conferir a quebra da impermeabilidade da casca da uva, estas são comumente imersas em soluções que contêm hidróxido de sódio (NaOH) (CARRANZA-CONCHA et al, 2012), carbonato de potássio (K 2 CO 3 ) (BINGOL et al, 2012) e carbonato de cálcio (CaCO 3 ) (GABAS et al, 1999). Porém, além de notar-se o benefício da aplicação dessas substâncias com relação ao tempo de secagem é preciso levar em consideração que a utilização de diferentes soluções com conteúdo químico pode prejudicar aspectos nutricionais dos produtos diminuindo teores de alguns parâmetros desejáveis, como o conteúdo de antioxidantes (CARRANZA-CONCHA et al, 2012).…”

“…Porém, além de notar-se o benefício da aplicação dessas substâncias com relação ao tempo de secagem é preciso levar em consideração que a utilização de diferentes soluções com conteúdo químico pode prejudicar aspectos nutricionais dos produtos diminuindo teores de alguns parâmetros desejáveis, como o conteúdo de antioxidantes (CARRANZA-CONCHA et al, 2012).…”