ABSTRACT
The aim of this study was to apply an edible coating containing prebiotics such as oligofructose and inulin to fresh-cut apple wedges. An assessment of the quality, sensory, polyphenol, and volatile attributes of coated and uncoated fresh-cut apple wedges was also undertaken. Fructan analysis showed that all prebiotics remained stable over the 14-d storage period and an intake of 100 g of apple supplies 1 to 3 g of prebiotics. Browning index, firmness, acidity remained stable throughout the 14 d compared to the control while applying prebiotic coatings resulted in an increase in soluble solids. Sensory and visual assessment indicated acceptable quality of apple wedges coated with prebiotics. HPLC analysis showed that levels of polyphenolic compounds were more stable in coated apple wedges (without prebiotic inclusions) than in uncoated control apples. No difference was found between O(2) and CO(2) headspace concentration of coated and uncoated samples. Significant differences (P < 0.001) were found for headspace volatile production between the samples. Most coated samples showed lower volatile production in the headspace than uncoated samples.
Subject(s)
Alginates/chemistry , Fast Foods/analysis , Food Preservation/methods , Fruit/chemistry , Inulin/chemistry , Malus/chemistry , Oligosaccharides/chemistry , Alginates/metabolism , Chemical Phenomena , Flavonoids/analysis , Food Handling , Food Packaging , Glucuronic Acid/chemistry , Glucuronic Acid/metabolism , Hexuronic Acids/chemistry , Hexuronic Acids/metabolism , Humans , Hydrogen-Ion Concentration , Inulin/administration & dosage , Inulin/analysis , Maillard Reaction , Odorants , Oligosaccharides/administration & dosage , Oligosaccharides/analysis , Phenols/analysis , Polyphenols , Prebiotics/analysis , Quality Control , Sensation , Surface Properties , Time Factors , Volatile Organic Compounds/analysisABSTRACT
In this study, the polyphenolic composition of skin-on apple wedges from ten cultivars was examined during chill storage and over two growing seasons. Individual polyphenol compounds were measured using HPLC resulting in the total polyphenolic index (TPI). Total phenolic content (TPC) was quantified using the Folin-Ciocalteu assay. Chilled storage had a significant effect (P < 0.001) on the polyphenol composition of all ten cultivars grown in 2007 and 2008. Total phenolic indices (sum of individual polyphenols) and TPCs of nine of the ten cultivars significantly decreased (P < 0.001) after 5 days of storage at 2-4 degrees C. These indices increased in case of Shampion apples over the same storage period. Changes in the most abundant compounds (-)-epicatechin, procyanidins and chlorogenic acid were largely responsible for changes in overall TPI. Percentage loss was higher for compounds such as phloridzin with a degradation of up to 100%. Irrespective of the different starting level of specific polyphenols in each year; storage resulted in a similar percentage loss/gain for each cultivar.
