Sharareh Rezaeian; Hamid Reza Pourianfar; Shadi Bolourian; Hamed Saberian
Abstract
Introduction: At the present, culinary-medicinal mushroom Enoki, Flammulina velutipes, ranks fifth among cultivated mushrooms in the world. Enoki has a delightfully crunchy texture and desirable taste. In addition, research has proved that this mushroom possesses substantial nutritional and medicinal ...
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Introduction: At the present, culinary-medicinal mushroom Enoki, Flammulina velutipes, ranks fifth among cultivated mushrooms in the world. Enoki has a delightfully crunchy texture and desirable taste. In addition, research has proved that this mushroom possesses substantial nutritional and medicinal properties. However, commercialization of Enoki is not yet expanded worldwide and it is still largely behind the other major edible mushrooms in some countries in west Asia (such as Iran). Based on our recent successful study on cultivation of Enoki in locally available lignocellulosic substrates, this study was aimed to evaluate the possibility of production of a novel functional drink based on Enoki mushroom supplemented with curcumin. Materials and Methods: A pure culture of the cultivated strain of Enoki was freshly fructified in a locally available lignocellulosic substrate composed of 40 % wheat straw + 40 % sawdust + 18 % wheat bran + 1 % lime + 1 % gypsum. The fresh fruiting bodies were crushed to different forms of pulp and puree to be utilized in the basic formulation of drink. Then, different concentrations of mushroom particles (5, 7.5 and 10 %) and pectin gum (0.05, 0.075 and 0.10 %) were used. Following pasteurization at 90 ºC for one minute, the rheological and sensory characteristics of the drink were evaluated. The viscosity and the flow behavior of the samples were measured at 7°C. A rotational programmable viscometer (LVDV-II Pro, Brookfield Engineering Inc., USA) with an LV spindle was employed. About 25 ml of each drink was poured into the cylinder of the viscometer and shear rate was measured from 5 to 200 s−1 within 5 s intervals. Effect of different treatments (pectin gum and mushroom concentration) on color indices of the Enoki drink was studied using colorimeter (ColorFlex EZ, Hunter Lab, USA) and indices of, L* (brightness), a* (redness–greenness), b* (yellowness–blueness), were determined. Some sensory characteristics (taste, odor, color, mouth feel, consistency, particle concentration and overall acceptance) of the Enoki drinks were evaluated by 12 trained panelists (aged 25–50 years) using a 5 level hedonic test (1, 2, 3, 4 and 5) from left to right representing unacceptable, relatively acceptable, good, very good, and excellent. Three types of flavor (Lime, tropical fruits and apple) were employed and the effect of the flavors on odor, flavor, taste and overall acceptance of the pulp- based drink was investigated. Finally, three concentrations of curcumin (0.01, 0.03 and 0.05 %), as a natural colorant, were used in the pulp- based drink and the overall acceptance of the panelists was evaluated in a separate test. Factorial tests based on the completely randomized design was employed to evaluate the effect of different concentration of mushroom and pectin gum. Results were analyzed by analysis of variance (ANOVA) using SPSS 19 statistical software and the Duncan’s test with 95% confidence interval was used to compare the means of the tests. The results which were presented in this research have been obtained from the average values of 12 replicates. Results and Discussion: Rheological tests showed that the flow behavior of the drink was pseudoplastic (or shear thinning), which indicated that the viscosity was decreased when the shear rate increased. All the samples had a yield stress at 7°C. Therefore, all the drink samples had a jelly form before exerting any stress, while the mushroom particles were completely suspended in the drink. From the panelists’ point of view, there was not any difference between the color of the drink containing different gum and mushroom, but L*, a* and b* values were significantly different. By increasing of the gum and mushroom concentration, brightness index (L*) increased. Sensory tests indicated that the highest and the lowest scores of flavor were related to samples containing 5 and 10 % (w/w) mushroom, respectively (p<0.05). Finally, the drink containing 5% mushroom puree and 0.05 % pectin gum was selected. The results of sensory evaluation showed that the drink containing mushroom pulp was significantly better than one containing mushroom puree (p<0.05). The overall acceptance of the Enoki drink containing lime flavor was the highest and there were not any significant differences between those containing apple and tropical fruits flavor. Furthermore, sensory acceptance of the drink increased by adding 0.05 % curcumin into it. It can be concluded that the drink containing Enoki mushroom pulp may have a good potential to be accepted by consumers. The use of a culinary-medicinal mushroom such as Enoki along with a natural colorant (curcumin) may make the drink a functional food without having any side effect. Overall, the findings of this study showed that the industrial production of this novel functional drink, with acidic lime taste and curcumin colorant, is feasible from a technical point of view.
