Physicochimical analyses of Italia raisins

Grapes (Vitis vinifera L.) cv. Italia were collected in two vineyards in North-Western Tunisia and dried into raisins by convector drying. 70 raisins were analyzed for each modality. The modalities were : the type of farming (conventional (Conv) or organic (Org)), the temperature of drying (50, 60 and 70°C for conv and 60°C for org), and the type of drying: no pre-treatment before drying (control :C), using a NaOH as pretreatment (SH), K2CO3 (CH), or cutting the raisin in two as traditional know-how (TRAD) and gathered at the end of the drying process, or in the organic type, TRAD by drying outside and not in a room with a controlled temperature (Sun_TRAD). The 70 raisins were divided in three replicates for analyses. Analyses: moisture content (MC) by AOAC method, pH, total acidity (TA), total soluble solids (TSS) by refractometry, protein and ash contents as well as the concentration of glucose, fructose, total sugars, malic and tartaric acids and total acids (by HPLC) while phytochemical characteristics comprise total polyphenol content (TPC) by spectrophotometry and the concentration of gallic, caftaric, coutaric and fertaric acids, catechin, epicatechin, procyanidin B2, quercetin-3-glucoside and rutin (by HPLC).