Relationship between the enzymatic determination of starch and the starch iodine index in two varieties of cider apple

Abstract

Monitoring the hydrolysis or disappearance of starch by the starch iodine test is a simple procedure for determining the maturity of cider apples, but it does not indicate the exact amount of starch present.

Impact of apple cultivar, ripening stage, fermentation type and yeast strain on phenolic composition of apple ciders

“…one month after the ripe stage: 6, 8, 10 and 12 weeks, respectively). Unripe apples had approximated starch index 1-2, ripe apples starch index 3-4 and overripe apples starch index 5 (Travers et al, 2002).…”

“…Ripening time and thus the harvesting time varies in each season due to varying weather conditions. Therefore the estimation of ripening stage was based on the assessment of the experienced farmer and additionally estimated using the iodine starch test under a laboratory setting (Travers, Jacquet, Brisset, & Maite, 2002). All apples were first harvested at the 'unripe' stage (0 weeks) of their maturity and left to ripen at +4°C.…”

Relationships between starch pattern indices and starch concentrations in four apple cultivars

“…Travers et al (2002) found a linear relationship between staining patterns (SPI) and starch concentration (%DM) of two cider cultivars. Seasonal variation in correlation between starch concentrations (g kg À1 in dry matter) and SPI were found in 'Fuji' and the AM to AP ratio of the starch may influence the ability to assess starch with iodine (Fan et al, 1995).…”

“…It is likely that the maximum starch concentrations in fruit is affected by cultivar, climate and position in the tree (Brookfield et al, 1997;Poapst et al, 1959;Smith et al, 1979). Also, the SPI only provides an indication of starch distribution and does not measure the starch content as precisely as other analytical methods (Cho and Gil, 2004;Peirs et al, 2003;Peirs et al, 2002;Travers et al, 2002).…”

“…Although the test was generally rejected as being too variable in early studies (Haller and Smith, 1950;Tiller, 1934), the indexing of the patterns based on visual assessment of starch staining has gained wide acceptance. The SPI test can be based on cultivar-specific charts such as for 'Delicious' and 'Northern Spy' (Smith et al, 1979), 'Granny Smith' , 'Empire', 'Idared' and 'Spartan' (Chu, 1988), 'Honeycrisp' (Hanrahan, 2012), or generic charts such as the Cornell 8-point chart (Blanpied and Silsby, 1992) and the European 10-point chart (Travers et al, 2002).…”