Investigation of physico-chemical and sensorial properties of functional fruit chips

Thesis Type: Postgraduate

Institution Of The Thesis: Bursa Uludağ University, ZİRAAT FAKÜLTESİ, GIDA MÜHENDİSLİĞİ, Turkey

Approval Date: 2019

Thesis Language: Turkish


Supervisor: Ömer Utku Çopur


In this study, two different types of fruit chips were produced in order to increase the shelf life of perishable fruits and develop an alternative product. For the production of apricot-peach (AP-C) and sour cherry-strawberry chips (SCS-C), the fruits were shredded (1: 1) and 13-15,6% sucrose, 1% pectin, 7% starch, 0,2-0,3% citric acid, 0,05% ascorbic acid, 1,7% maltodextrin and 12% water were added respectively. Obtained homogeneous mixture was dried with a vacuum dryer at 75 ° C 400 mbar. Total dry matter content of the fruit mixtures and chips was measured as 32,80±0,04, 82,41±0,10, 32,50±0,07 and 72,03±0,22 g/100g for AP-M, AP-C, SCS-M and SCSC, respectively. pH of the mixture (AP-M, SCS-M) was determined as 3,92±0,01, 3,57±0,01 and the amount of water-soluble dry matter of mixture (AP-M, SCS-M) was determined as 29,37±0,12, 29,97±0,15 g/100g respectively while ascorbic acid content of the chips (AP-C, SCSC) was determined as 5,61±0,37, 9,62±0,10 mg/100g respectively. Total acidity content of the mixture and chips were ranged between 0,76±0,00-1,02±0,00 g/100g while L*, a*, b*, chroma (C*) and Hue (h°) color values were ranged between 29,12-49,82, 13,44-41,31, 7,66-35,77, 21,08-47,36 and 21,30-69,41 respectively. Hydroxymethylfurfural (HMF) content of fruit chips was found to be 18,27±0,29 and 27,34±0,40 mg/kg for AP-C and SCS-C, respectively. Additionally, total phenolic content (TPC) and total antioxidant capacity (TAC) were determined both with chemical and physiological extraction (in vitro gastrointestinal digestion). TAC of chemical and physiological extracts were determined as 3,44±0,03-11,68±0,18 and 0,88±0,02- 2,02±0,05 μmol trolox/g dm (dry matter) in DPPH, 2,31±0,04-13,71±0,06 and 1,88±0,10- 19,81±0,12 μmol trolox/g dm in CUPRAC and 9,68±0,03-57,28±1,03 and 6,42±0,11-43,80±0,10 μmol trolox/g dm in FRAP assays. TPC of samples analysed in chemical and physiological extracts were measured between 118,25±0,14-381,78±0,90 and 126,04±0,75-418,09±0,36 mg GAE/100g dm respectively. When the effect of drying process on the mixture was examined, it was seen that TPC of fruit chips decreased in chemical and physiological extractions compared to the non-dried mixture. TAC values of both chemical and physiological extractions showed a decrement in antioxidant capacity by drying in DPPH and FRAP methods while an increment was recorded in CUPRAC method. In addition, sensory analysis was carried out considering color, appearance, odor, taste and overall acceptibility criteria of fruit chips and all samples were found acceptable. The flavoring of the fruit by acid and sugar addition and vacuum drying has enabled the production of an alternative fruit chips which were accepted in terms of sensorial properties.