Utilization of tuna roe and using inulin as oil replacer for producing value added omega-3 mayonnaise product

Abstract

Background: Fishery industry has been important for Thai’s economic more than 30 years. It leads Thailand to be the one of world’s largest canned tuna producer and exporter. However, mainly white meat part is used in canned tuna product while the waste comprises roe, viscera, head and dark meat is sold to feed meal plant or sold as cheap material even its nutritive value is still high. There is well know that sea fish as tuna is a good source of polyunsaturated fatty acid (PUFA) such as Eicosapentaenoic acid (EPA) and Docosahexanoic acid (DHA). Many people around the world play more attention with salad dish with the dressing. Generally, mayonnaise is prefer for the salad dressing and it normally consists of chicken egg yolk which high saturated fatty acid and in addition, fat content in mayonnaise normally is about 30-65%. Therefore, normal mayonnaise is high in fat content and low polyunsaturated fatty acid then consuming this product may not a great idea for on diet or controlled weight people.

Objective: To increase omega-3 by tuna roe substitution and to replace fat content by using inulin gel.

Methods: Tuna roe was prepared by soaking with galangal extracted with 95% ethanol for removal fishy/rancidity odor. Inulin powder 45 g was added in to water to obtain final suspension 100 ml before brought to heat at temperature 65^oC for 15 min to form a gel and stored at 4^oC. Omega-3 mayonnaise product was started with using 100% tuna roe substitution for egg yolk. Thereafter, inulin gel was added to replace vegetable oil at 0, 25, 50, 75 and 100%. Basic mayonnaise containing egg yolk and 0% inulin gel (100% soy bean oil) was used as control sample. Color and emulsion stability test were monitored for physical quality. pH value, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were used for chemical quality. Total viable count (TVC), yeast and mold, lactic acid bacteria (LAB) and coliform were measured for microbiological quality. Sensory evaluation using 9-point hedonic scale technique was also monitored.

Results: When increased inulin gel into the mayonnaise, L* value significantly increased while a* and b* values significantly decreased (p<0.05). Without added inulin gel, mayonnaise producing by using tuna roe had lower emulsion stability test (%) compared with control sample using egg yolk. It was found that using inulin gel significantly increased moisture contents and water activity of mayonnaise. However, there was no significantly different found in pH value in any sample. In addition, tuna roe mayonnaise with and without added inulin gel possessed higher lipid oxidation products determined as PV and TBARS value compared with basic mayonnaise using egg yolk. All microbiological quality indices were very low and passed standard regulation of mayonnaise product. Though, consumer acceptability of mayonnaise producing from tuna roe was lower than that of control, 50% of inulin gel substitution seemed to have better sensory score when compared with other inulin gel substitution groups. Therefore, sensory improvement of omega-3 mayonnaise product substituted with inulin gel need to be further studied.

Conclusions: Mayonnaise producing from tuna roe and replacing fat with inulin gel between 25 to 100% were successful when determined by emulsion stability, pH value and microbiological quality. However, sensory score of using 100% tuna roe with and without inulin gel substitution for making mayonnaise was lower than that of control. Among tuna roe mayonnaise substituted with inulin gel, 50% should be selected for sensory improvement in the further work.

Keywords: Tuna roe, Mayonnaise, Inulin, Omega-3