Consumer acceptance and physicochemical quality of processed red sorrel/roselle (Hibiscus sabdariffa L.) sauces from enzymatic extracted calyces

Abstract

The objectives of this study were to utilize sorrel puree from enzymatic extracted sorrel or roselle (Hibiscus sabdariffa L.) calyces in the processing of sauces and to determine consumer acceptance of sauces with the addition of 0.3% and 0.4% xanthan gum. The physicochemical (particularly colour) and microbial quality changes in sauces were monitored during storage. Pectolase treatment of sorrel calyces resulted in a high yield (94.5%) of puree, but the hue changed (P < 0.05) from red to orange-yellow. Adjustment of puree to pH 2.3 resulted (P < 0.05) in an intense red colour. Sensory and physicochemical attributes did not differ significantly between sauces except for consistency and hue. Sensory colour was the most liked (P < 0.05) attribute with an instrumental colour ‘L’ 23.5, ‘a’ 3.5 and ‘b’ 0.40. Total soluble solids and pH were 41.0–43.5°Brix and 2.62 ± 0.04, respectively. Sauces were liked slightly to moderately in overall acceptability. A positive correlation (P < 0.05) was noted between the overall acceptability to other sensory attributes. Colour became less dark and red (P < 0.05) on storage at 20°C for 6 weeks. Sauces had < 10 cfu/mL of yeasts and moulds, lactobacilli and total mesophilic aerobes throughout storage at 20°C for 8 weeks. A 25-g sauce serving provided 0.7-g dietary fibre or 3% of the daily value. The overall acceptability of sorrel sauce makes it an ideal ingredient for use in the food service industry and inclusion in a number of dishes.