engleski

Enrichment of apple puree with addition of sugars and apple peel powder

Phenols play an important role in physiologic functions related to human health. To improve the quality of fruit products, common approach is to apply less invasive process or to use specific additives. Among several apple varieties (grown in local region) Granny Smith (GS) and Gold Rush (GR) were chosen for preparation of apple puree. Current trends in food industry are exploitation of natural and industrial resources, thus in our research, we used apple peel powder as ingredient for enrichment of apple puree. Next to apple peel powder addition (5%), sugars were also added (1, 5, and 10% of glucose, fructose, sucrose or trehalose) and influence on apple puree phenols (TPC) and antioxidant activity (AA) was studied. Samples of apple puree were processed by freezing and freeze-drying. Apple puree without additive addition was used as control. Control sample of frozen GS had TPC and AA 0.4 g/kg and 6 mmol TE/100g, respectively, and freeze-dried puree 0.45 g/kg and 5.6 mmol TE/100g, respectively. Frozen GR sample had TPC and AA 0.61 g/kg and 13.69 mmol TE/100g, respectively, and freeze-dried puree 0.64 g/kg and 8 mmol TE/100g, respectively. In samples obtained by freezing, the highest TPC (1.78 g/kg) and AA (25.15 mmol TE/100 g) had GS with addition of apple peel powder and 5% sucrose. Considering only influence of sugar, the highest TPC (0.96 g/kg) and AA (16.36 mmol TE/100g) had GR with 5% of trehalose addition. Freeze-dried samples had lower values of investigated parameters. The highest TPC (1.69 g/kg) and AA (24.32 mmol TE/100 g) had GR with addition of apple peel powder and 1% trehalose. Considering only influence of sugar, the highest TPC (0.95 g/kg) and AA (14.05 mmol TE/100g) had GR puree with 1% of sucrose addition. Processing method, sugar and apple peel powder addition highly influenced TPC and AA of samples. Our results could be worthwhile with respect of development of functional foods using apple by-product.

sugar addition; phenolic compounds; apple puree

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