Utilising Spent Tea Leaves Powder as Functional Ingredient to Enhance the Quality of Non-Gluten Shortbread Cookies

Abstract

The increasing prevalence of gluten-related disorders has led to higher consumer demand for convenient, gluten-free bakery products with health-promoting properties. In this study, non-gluten shortbread cookies were incorporated with various kinds of spent (green, oolong, and black) tea leaves powder (STLP) at 8% w/w. Cookies with STLP had significantly higher (p < 0.05) moisture (2.18–2.35%), crude fibre (14.5–14.9%), total dietary fibre (22.38–22.59%), insoluble dietary fibre (15.32–15.83%), soluble dietary fibre (7.06–7.66%), and ash (1.9–2.0%) contents, but were significantly lower (p < 0.05) in carbohydrate (53.2–53.9%) and energy value (426.4–428.2 kcal) compared to control cookies (1.62%; 1.43%; 6.82%; 4.15%; 2.67%; 7.70%; 62.2%; and 457.8 kcal, respectively). The addition of STLP significantly enhanced (p < 0.05) the antioxidant properties of the cookies. Non-gluten shortbread cookies with spent green tea leaves powder (GTC) received the highest (p < 0.05) score for all sensory attributes, including overall acceptability. In addition, the shelf-life quality of the formulated cookie samples in terms of the moisture content, water activity, colour, texture, microbiology, and sensory properties was maintained (p > 0.05) for at least 22 days at 25 °C. STLP, which would have been previously thrown away, could be utilized as a potential functional ingredient to produce non-gluten shortbread cookies with enhanced nutritional, physicochemical, microbiological, sensory, and antioxidative properties.

The Bioactive Substances in Spent Black Tea and Arabic Coffee Could Improve the Nutritional Value and Extend the Shelf Life of Sponge Cake after Fortification

“…Our results are comparable to those of Koh et al, who found that the tannin level of all the cookies made with spent tea powder was much higher than that of the control cookies. The high tannin content of the spent tea powder may be blamed for this.…”

“…The heat breakdown of tannin during baking may be to blame for this . According to the findings, all of the cookies’ tannin concentration was within the allowed level for their antinutritional effect when consumed by humans …”

“…This is because the brown color is too dark to be seen, related to the rise of a * value and the reduction of b * value . Additionally, the L *, b *, and a * values of the spent tea powder-infused cookies were much lower than those of the control cookies, showing that the inclusion of spent tea powder gave the cookies a darker hue . These might be related to the original color of spent tea powder due to spent tea powder containing high amounts of phenols, making it darker in color than wheat flour.…”

“…Flour contains a variety of microflora in addition to molds . In addition, the inclusion of spent coffee grounds in the formulations of the biscuits and spent tea grounds in the formation of cookies did not increase the microbial count, indicating that the food item has good microbiological quality …”

“…In contrast, Cr and Cd were not found in any of the cake samples and Se had no significant effect on any of the samples. Reports have indicated that fortifying bakery products with coffee or tea can significantly increase their elemental contents including Ca, K, and Mg. 58,59 Total Secondary Metabolites. In baked goods, samples of cakes supplemented with 1, 2, and 3% spent tea and coffee powder showed an increment in the total phenols and total tannin content compared to the control cakes.…”