Browsing by Author "Oinonen, Iida"

Japanese quince (Chaenomeles japonica) is a fruit crop that can be used for example in the production of jams, marmalades, juices, soft drinks, and alcohol beverages. Pressing juice from Japanese quince fruits produces large amounts of pomace as a side stream. The aim of the study was to examine the chemical composition of Japanese quince cultivars that are being cultivated in Finland. Both fruits and fruit pomaces were analysed. The effect of enzyme-assisted water extraction on dry matter yield from Japanese quince pomace was also investigated. Fruits and pomaces of cultivars Sirius, Venus, and seed offspring of cultivar Cido were used as research material. Determination of chemical composition was conducted with the analyses of dry matter, lipids, dietary fibre, ash, protein, and carbohydrate content. Fatty acids were extracted with accelerated solvent extraction and were analysed with gas chromatography (GC-FID). With pomaces four different extractions were made: one with plain water extraction, one assisted with pectinase enzyme, one assisted with cellulase enzyme, and one assisted with both pectinase and cellulase enzymes. Dry matter yield of extracts was measured, and extracts were also filtered with ultrafiltration (UF). UF permeates were analysed with ELSD-UPLC to detect sugars and organic acids from the extracts. According to this study cultivar had a significant impact (p < 0.05) on dry matter, protein and lipid content and fatty acid composition of fruits. With pomaces there were also significant differences in dietary fibre contents. Most of the dietary fibre was insoluble dietary fibre. The main detected fatty acids were C16:0, C18:1 (n-9) and C18:2 (n-6). Water extraction assisted with both pectinase and cellulase enzymes had significantly higher extraction yield (29.5%) compared to water extraction assisted with cellulase enzyme (24.2%) and plain water extraction (26.4%) which did not differ statistically (p < 0.05). Extraction yield from pectinase assisted extraction (28.4%) differed only with the yield from cellulase assisted extraction (p < 0.05). All the permeates contained mostly malic acid. Fructose, glucose, and little amount of sucrose were also detected. There were only little differences between composition of permeates. Chemical composition of fruits may vary between growing seasons and thus, repeating the analyzes during several harvest seasons would provide more information on what kind of effect growing season has on fruit composition. This study also raised further questions on what kind of impact of pretreatments prior enzyme assisted extraction could have on the extraction yield.