Reduction of Unpleasant Perceptive Intensity and Primary School Lunch Vegetable Waste by Sauce Flavoring

High school lunch waste, vegetable most, is a global issue. Vegetable species and preparation methods affected their acceptance and plate waste. Thermal process was demonstrated to reduce bitterness contents and seasoning to mask perception intensity, and thus improve vegetable consumption. In this study, the effect of culinary practice (blanching and seasoning addition) of broccoli, a common vegetable served in school lunch, on sensory characteristics (acceptance and perception intensity of astringency, bitterness, grassy smell and sweetness) was determined first. Moreover, the contribution of culinary practice application on vegetable waste in a primary school was assayed. Broccoli was prepared: raw (C), blanched (B), blanched and flavored with Japanese style sauce (Flavor-1), with cheese (Flavor-2), and with Chinese style sauce (Flavor-3). Our results showed raw materials exert the strongest perception intensity of grassy smell, bitterness and astringency but the least intensity of sweetness. Blanching and seasoning addition masked perception intensity and thus enhanced likeness of odor, flavor and overall acceptance. Blanching treatment, overall acceptance was significantly negatively correlated to intensity of grassy smell. While seasoning incorporation, overall acceptance was positively correlated to sweetness intensity and negatively correlated to astringency intensity. Application of culinary practice improved palatability and thus reduced vegetable rejection. The aggregated vegetable wastes for 4 consecutive semesters from July, 2020 to June, 2021 (87±3 day/semester) were as low as 6.5% per day.