Effect of drying method on physical and chemical quality, hotness and volatile flavour characteristics of dried chilli

Abstract

The effects of drying methods, such as sun drying at 37oC, hot air drying at 60oC and freeze drying, on the quality of dried Chee fah chilli (Capsicum annuum Linn. var. acuminatum Fingarh.) were investigated. The quality parameters were moisture content, colour (L*, a*, b* values), ascorbic acid content, capsaicin content, volatile flavour and sensorial description. The freeze-dried (FD) sample gave more bright-red colour and contained higher ascorbic acid content than the sun-dried (SD) and hot air-dried (HD) samples (P < 0.05). Meanwhile, moisture content (11%) and capsaicin content (1 ppm) were not significantly different among the three drying methods (P > 0.05). Types and concentrations of volatile flavour compounds were monitored using headspace solid phase microextraction (HS-SPME) with a gas chromatography-mass spectrometry (GC-MS). The groups of volatile flavour compounds were acids, alcohols, ketones, aldehydes, esters, furan and hydrocarbons. This was in agreement with the panelists who described the pungent odour as the most abundant one. In addition, the unique flavour attributes in the FD, HD and SD samples were green, sweet and alcohol-linked, respectively.