Title: Savoury flavour formulations from maillard reaction of hydrolysated cod by-products and sugars.

Author(s): Min Qu
Final project
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Supervisors: Hjorleifur Einarsson
Flavour; cod; by-product; Maillard reaction; response surface methodology; fish sauce.


On a world scale, more than 20 million tons of the fish production is turned into non-food products. These by-products contain proteins and fish oils that can serve as a raw material for valuable products. Hydrolysis, autolytic or by enzymes, is one way for protein recovery. In South-East Asia fish sauces are an example of auto-hydrolysed products having strong and enhancing fish flavour. The aim of this study was to test if fish by-products could be used as a source of savoury reaction fish flavours. In this study a fish protein hydrolysate (FPH) was produced by enzymatic hydrolysis of minced cod cut-offs (CCHs). The resulting FPH was heated in the presence of sugars to produce reaction fish flavours (fish sauce analog) in the Maillard reaction (MR). Low degree of hydrolysis (DH) (38.6%) of CCHs were obtained by the combination of 1% of Protamex® and 1% of Flavourzyme® however approximately 70% of the proteins were found in the clear supernatant. After heating the FPH in the presence of 1% sugars, xylose and lactose enhanced the fish sauce-like flavour but glucose, ribose and fructose less. The Maillard reaction products (MRPs) from xylose heated for more than 1.5 hours at 80°C gave the characteristic fish sauce flavour but the lactose mixture had a typical and strong fishy flavour. With increasing reaction time, the fishy flavour decreased while the burnt flavour was enhanced. The optimal conditions of the parameters (xylose concentration, reaction temperature and reaction time) for colour production were determined by RSM targeting also optimal fishy and burnt flavour tones. Based on the results from the RSM a fish sauce analog (FSA) was produced using 1.5% of xylose heated together with FPH at 90 ℃ for 0.93 hours. The FSA had a deep brown slightly reddish-yellow colour having strong fishy and burned flavour. The protein content was 13.6% and it hat 3.0% salt. It is concluded that FPH made from cod-cut offs can be used as a raw material for the production of fish reaction flavours. The product could be marketed as a low salt alternative in SA-Asia and elsewhere where fish sauces are used in food formulations.

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