Nutrient Content and in Vitro Digestibility of Apple Pomace Derived from Three Different Apple Cultivars

Abstract

This study focused on evaluating the nutritional characteristics and in vitro true digestibility of apple pomace derived from three apple cultivars: Golden Delicious, Starking, and Granny Smith (Malus domestica Borkh). These apple cultivars were sourced from the local market in Nigde, Turkiye. Statistical analyses, including one-way analysis of variance (ANOVA) and Duncan's test, were employed to assess variations among the apple pomace samples. Results indicated that, except for in vitro true digestibility, there were no significant variations in the chemical composition and total phenolic matter contents among the apple pomaces (P>0.05). However, Granny Smith apple pomace exhibited distinct features, such as higher neutral detergent fiber content (29.80%), elevated crude protein levels (5.09%) and substantial acid detergent fiber (25.30%) values. In contrast, Starking apple pomace displayed superior air-dry matter (27.24%), while Golden Delicious showcased enhanced dry matter (95.3%) and ash content (2.00%). Regarding total phenolic matter contents, Granny Smith excelled with 112.4 mg GAE/100g, outperforming Starking (103 mg GAE/100g) and Golden Delicious (75.8 mg GAE/100g). Crucially, Starking demonstrated superior in vitro true digestibility, with values reaching 92.36% (as received) and 92.23% (dry matter). Granny Smith, in comparison to Golden Delicious and Starking, displayed significantly different neutral detergent fiber digestibility (P<0.05). Starking apple pomace exhibit the highest overall digestibility among the apple pomaces analysed in this study, hence recommended for use in ruminant nutrition. These findings have implications for the potential utilization of apple pomace in diverse applications, given the diverse nutritional profiles of these cultivars.

Keywords

• agro-industrial waste products
• nutritional value
• apple pomace
• in-vitro digestibility
• ruminant feeding