Bioproduction of Natural Isoamyl Esters from Coconut Cream as Catalysed by Lipases

Shao Quan Liu,Huey Yie Lee,Jingcan Sun,Philip Curran,Bin Yu

doi:10.5539/jfr.v2n2p157

Abstract

<p>This study investigated the bioproduction of isoamyl esters in coconut cream by lipases. Five lipases (palatase 20000 L, lipase AYS “Amano”, lipase A “Amano” 12, piccantase A and piccantase AN) were used to biosynthesize isoamyl esters in coconut cream supplemented with isoamyl alcohol. The lipases have different abilities to synthesize isoamyl esters with lipase AYS “Amano”, palatase 20000 L and piccantase A showing the highest potential. Bioproduction of isoamyl octanoate by palatase 20000 L was further examined under different conditions of temperature, pH, isoamyl alcohol concentration and lipase amount. Biosynthesis of isoamyl octanoate by palatase was not significantly affected at 30-50°C or pH of 4 to 7 and its maximum bioproduction was obtained at isoamyl alcohol concentration of 4% (v/v) and lipase amount of 6 mg 100 mL<sup>-1</sup> reaction mixture. The lipase-treated coconut cream may serve as a bioflavouring ingredient for food applications or for extraction of pure aroma chemicals.</p>

Highlights

Esters of short-chain fatty acids, aromatic and acetate esters are arguably the most important aroma chemicals in food and beverages such as wine, imparting various fruity flavour notes (Cristiani & Monnet, 2001; Ugliano & Henschke, 2009)
This study aimed to investigate the bioproduction of isoamyl esters from coconut cream and isoamyl alcohol with a focus on aroma-active isoamyl octanoate
Palatase 20000 L and piccantase A were isolated from Rhizomucor miehei, lipase AYS “Amano” was obtained from Candida rugosa, and lipase A “Amano” 12 and piccantase AN were produced from Aspergillus niger

Summary

Introduction

Esters of short-chain fatty acids, aromatic and acetate esters are arguably the most important aroma chemicals in food and beverages such as wine, imparting various fruity flavour notes (Cristiani & Monnet, 2001; Ugliano & Henschke, 2009). Isoamyl esters of short-chain fatty acids of C2-C8 are commonly used in flavour compositions for foods and beverages (Arctander, 1994). Examples of such flavour compositions include banana, apricot, apple, cherry, peach, strawberry, raspberry, pineapple, chocolate, candy, chewing gum, honey, butter, butterscotch, coffee, rum, liqueur, and brandy etc. The increasing consumer demand has led to a rapid shift toward the production and use of natural flavour compounds. More commercially acceptable alternatives are biocatalysis and fermentation using enzymes and microorganisms such as yeasts (Cristiani & Monnet, 2001; Longo & Sanroman, 2006; Ugliano & Henschke, 2009; Tan et al, 2011)

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