Drinkable beverage based on whey and Opuntia stricta(var. dillenii) juice derived from underexploited biowaste: from process development to characterization

The formulation of a new functional beverage from Opuntia strictajuice enriched with whey cheese was investigated. Five beverages were developed with different percentages of juice. The storage stability was evaluated at 4 °C during 60 days in terms of physicochemical analysis (pH, acidity, total, and reducing sugar). The prepared beverages have a red color and a highly acceptable taste, the overall acceptability varies from 6.12 to 6.80 and from 7.16 to 8 respectively for the two categories of consumers 10–25 and over 25 years old. The relation between acceptability of beverages (for two categories of consumers) and sensory parameters (color, juice percentage, taste, and texture) was modelized using linear regression model with a correlation coefficient (R2) of 72.9% and 70.5% respectively for consumers 10–25 and over 25 years old. In this vein, the beverages were appreciated differently according to the age range of consumers (10–25 years or over 25 years old). A mathematical relationship between the responses (pH, acidity, reducing, and total sugars) and covariates (storage period and juice concentration) was obtained, described by first-order polynomial equations with an R2of 87%, 83%, 89.5%, and 88.7% respectively for pH, acidity, reducing, and total sugar. The study showed that the drinkable beverage based on whey and Opuntia strictajuice with a proportion of juice varying from 35 to 25% is the best regarding sensory properties and physicochemical stability.