Sensory attributes of dishes containing shrimp paste with different concentrations of glutamate and 5′-nucleotides

The shrimp paste called belacan is a traditional umami taste condiment extensively used in Malaysia that is rich in glutamate and 5′-nucleotides. The aim of this study was to determine the concentration of glutamate and 5′-nucleotides of various types of foods prepared with belacan and to measure their sensory attributes. The concentration of free glutamic acid found in different brands of belacan was 180-530 mg/100 g and in local dishes 601-4207 mg/100 g. The total amount of 5′-nucleotides in belacan samples ranged from 0.85 to 42.25 μg/g. A Quantitative Descriptive Analysis (QDA) using a list of 17 sensory attributes showed a good correlation between belacan concentration in the final food and a range of positive sensory attributes, except for bitter, sweet, sour taste and astringency. Belacan also contains bitter, sweet and sour compounds that change the positive attributes of belacan at higher concentrations. The highest aroma attributes were linked to nasi goreng belacan (belacan fried rice) while the highest flavour attributes were found in sambal belacan. There was a 32 folds significant increase of umami attributes with the addition of belacan to final foods. The optimum amount of belacan was 0.45% for asam pedas (tamarind flavoured dish with belacan), 18% for sambal belacan (chilli belacan), 1.5-2.5% for kangkong goreng belacan (stir fried water convolous with belacan), and 2% for nasi goreng belacan.