Phenolic content and some physical properties of dried broccoli as affected by drying method

Abstract

Broccoli samples ( Brassica oleracea) with an initial moisture content of 82.87% (wb) were dried using microwave technology (18, 36, and 54 W/g). Convective drying was used as a control group. The dependent variables investigated in the study were phenolic content, color, rehydration capacity, and microstructure of broccoli samples. Moreover, the best fitting thin layer model to the experimental moisture ratio was determined. The phenolic contents were found as 892.4, 740.6, and 759.8 mg gallic acid/100 g dry matter for fresh, convective dried, and microwave (MW) dried at 54 W/g broccoli samples, respectively. The total phenolic content of samples dried at 54 W/g was closest to fresh samples compared to other MW power intensities and convective drying. A similar result was obtained for color values too. L*, a*, and b* of microwave-dried samples at 54 W/g were comparable to fresh broccoli. Another important result obtained from the study was the insignificant effect of drying conditions on rehydration capacity. In addition, it was found that microwave power had a positive effect on drying time; as the microwave powers applied were compared, the shortest drying time was reached at 54 W/g. When the process durations of microwave drying and convective drying were compared, it can be reported that a much lower process time for microwave drying was obtained with respect to convective drying. Drying in microwave oven has reduced the drying time by 49-52%. In the light of the results obtained, it may be declared that it is possible to produce high-quality dried broccoli samples in a very short time by using microwave drying at 54 W/g.

Physical-Functional Properties and Characterization of Green Leaves in Nalgonda District, Telangana State: Nontimber Forest Products

“…The following characterization methods were used in this study: rehydration capacity (Quintero-Ramos et al 1992), shrinkage capacity (Yilmaz et al 2018), relative reconstitution capacity (Fathima et al 2001), dehydration and rehydration ratio (Sheshma and Raj 2014), bulk density (Stojceska et al 2008), tapped density (Narayana and Narasinga Rao 1984), flowability and cohesiveness (Jinapong et al 2008), titratable acidity (Ranganna 2017), total soluble solids (TSS; Kathiravan et al 2014), color (Hunter Lab 2013), chroma and hue (Pathare et al 2012), total color difference (Martins and Silva 2002), water solubility and water absorption index (WAI; Anderson et al 1969), waterretention and oil-retention capacities (Beugre et al 2014), hydrophilic lipophilic index (Njintang et al 2001), and water activity (Abramovie et al 2008).…”

Investigation of herbal extracts from St John’s wort (Hypericum perforatum) and geranium (Perlargonium graveolens) and their usage as instant herbal tea

“…Ekstraksiyon işlemine başlamadan önce örnek çözgen oranının belirlenebilmesi için sarı kantaron ve ıtır ham maddelerinin nem miktarları infrared nem tayin cihazı (MA150, Sartorius, Germany) ile belirlenmiştir [23].…”

Drying Characteristics and Heavy Metal Levels in Three Marine Fishes Commercialized in Brazil / Características De Secagem E Teor De Metais Pesados Em Três Espécies De Peixes Marinhos Comercializados No Brasil

“…where Mt, M0 and Me are moisture content at any time of drying (kg water/ kg dry matter), initial moisture content (kg water/ kg dry matter) and equilibrium moisture content (kg water/ kg dry matter), respectively. The Me was neglected since its values are relatively small compared to Mt and Mo [18][19].…”

“…where MRexp,i is experimental moisture ratio, MRpre,i is predicted moisture ratio, N is the number of observations, Z is the number of constants. The model that best describe the drying characteristics was chosen as the one with the highest R 2 , followed by the least χ 2 and RMSE values [19,21].…”