The effect of exogenous pectinase on DMHF and derivatives in clarified strawberry juice (Fragaria × ananassa, cv. Elsanta)

Abstract

The effect of exogenous pectinase on the levels of 2,5-dimethyl-4-hydroxy-2H-furan-one (DMHF) and DMHF-glucoside was studied in clarified strawberry juice (Fragaria ð ananassa, cv. Elsanta). The extent of conversion of DMHF-malonyl glucoside to DMHF-glucoside and DMHF was monitored at three different temperatures (45°C, 50°C and 60°C) and at three different pH values (pH 3.0, 4.0 and 5.4). The effect of using two different concentrations of pectinase was also studied. Based on these results, the endogenous levels of DMHF-malonyl glucoside were calculated for the first time in strawberries.

Concentrations of Character Impact Odorants in ‘Toyonoka’ Strawberries Quantified by Standard Addition Method and PQ Column Extraction with GC-MS Analysis

“…The concentration of DMHF was found to be 19.7 mg•kg −1 FW, the highest in all character impact compounds (Table 3). The contents of DMHF in quantitative experiments are generally lower than 20 mg•kg −1 FW, for example, 2.2-6.3 mg•L −1 in 'Red Gaunlet' and a wild strawberry in Switzerland (Pickenhagen et al, 1981), 11.7 mg•kg −1 FW in 'Senga Sengana' , and 0-11.5 mg•kg −1 FW in 'Dania', 'Bogota', and 'Senga' , cultured in Denmark, 16.2 mg•kg −1 FW in 'Italy' cultured in Germany (Schieberle, 1994), 1.15 .4 mg•kg −1 FW in 'Korona', 'Pandora', 'Bogota', 'Pegasus', 'Senbana', and 'Elsante' cultured in Germany (Sen et al, 1991), <16 mg•kg −1 FW in 'Redcrest', 'Chandeler', 'Pajaro', 'Benton', and 'Parker' cultured in the USA (Sanz et al, 1995), 3.3-19.0 mg•kg −1 FW in 'Cuesta', 'Seascape', 'Sunset', 'Laguna', 'Carlsbad', 'Cartcua', 'Cartuno', and 'Camarosa' cultured in Spain (Perez et al, 1996), about 10 mg•kg −1 FW in 'Elsanta' cultured in the UK (Mura and Zabetakis, 2002), and 6.8 mg•kg −1 FW in 'Cigaline' cultured in France (Menager et al, 2004). The DMHF concentration was found to be >20 mg•kg −1 FW in a hybrid between a wild strawberry and 'Chandler' in Germany (Sen et al, 1991), 'Douglas' and 'Totem' cultured in the USA (Sanz et al, 1995), 'Elsanta', 'Pandora Sengana', and 'Elvira' cultured in Denmark and 'Chandler', 'Tudla', 'I-101', and 'Oso Grande' cultured in Spain (Perez et al, 1996); therefore, the level of DMHF in 'Toyonoka' is relatively high for strawberry cultivars.…”

“…More than 360 volatile compounds have been identified in strawberries (Latrasse, 1991) by diversified extraction and analysis methods (Gomes da Silva and Chaves das Neves, 1999; Hakala et al, 2002;Park et al, 2000;Pyysalo et al, 1979;Schieberle, 1994;Urruty et al, 2002). Regarding the quantified study of volatiles in strawberries, although high performance liquid chromatography with either ultraviolet radiation (Mura and Zabetakis, 2002;Sanz et al, 1994Sanz et al, , 1995 or photo diode array (Zabetakis and Holden, 1996) detection has been used recently, GC analysis is the most frequent method for the separation of volatile compounds (Forney et al, 2000;Zabetakis and Holden, 1997). In analyses with a GC-flame ionization detector or GC-MS, the content of volatile compounds has been generally estimated by the relative concentration of one or several internal standards added during extraction or of external standards added before analysis (Dirinck et al, 1981;Douillard and Guichard, 1990;Fischer and Hammerschmidt, 1992;Hirvi, 1983;Kollmannshberger and Berger, 1994;Park et al, 2000;Perez et al, 1996;Pickenhagen et al, 1981;Pyysalo et al, 1979;Schreier, 1980;Siegmund et al, 2001;Ulrich et al, 1997).…”