Effects of roasting on chemical composition and quality of different chestnut (Castanea sativa Mill) varieties

In view of the ongoing revival of the chestnut orchards in southern Switzerland, evaluation of chestnut quality represents an important issue. Chestnuts are mainly consumed roasted. Three native varieties and a French one were roasted and submitted to sensory and chemical analysis in comparison to a commercial marrone variety imported from Italy. Weight loss due to roasting ranged from 23 to 30%. Roasted chestnuts contained 260-350 g kg(-1) starch, 50-102 g kg(-1) sucrose, 0.5-4.4 g kg(-1) fructose, trace amounts of glucose and 9-15 g kg(-1) total fatty acids. The main fatty acid in chestnuts was linoleic acid, amounting to 49% of total fatty acids. Sensory analysis showed that acceptance of chestnuts was highly dependent on sweetness, which was related to sucrose content. It should be at least 90 g kg(-1). Varietal differences were observed in this study and it was shown that roasting caused little change in composition. Thus chestnut varieties used for roasting have to be selected accordingly. The commercial variety Marrone di Cuneo confirmed its superiority with regard to suitability for roasting. Among the Swiss varieties, only Luina exhibited satisfactory quality. (C) 2001 Society of Chemical Industry.