Food that is still fit for consumption is wasted in the domestic environment every day, so food packaging technologies are being developed that will monitor the quality of the products in real time. Highly perishable milk is currently one of the products that suffers most from this waste, due to its short shelf life. Active use-by date (AUBD) indicators have been shown to discriminate between fresh and spoiled milk. Colorimetric indicators undergo characteristic changes in their chemical structure, causing abrupt color changes. Among the polymeric materials studied that may function as solid support are cellulose acetate (CA) and agar-agar (AA). The AA colorimetric indicator proved to be more suitable as a solid support due to its ability to maintain the color change properties of the anthocyanin and its high colorimetric performance. The technique was shown to be capable of indicating, in real time, changes in milk quality.
Environmental pollution and food safety are both issues of global concern. In this sense, sustainable and antimicrobial nanocomposites based on cellulose/poly (vinyl alcohol) blend incorporated with natamycin and cellulose nanocrystals (CNC) were manufactured and characterized. The developed films were evaluated according to their mechanical and optical properties, and their barrier to oxygen and water vapor permeation. The antimycotic activity was evaluated in vitro against fungi and yeasts. The film’s potential to act as an active packaging for Minas cheese preservation was also assessed. The incorporation of CNC increased the films’ tensile strength; however, it did not influence the barrier properties to water vapor (4.12 × 10−7 g·cm.m−1·h−1·Pa−1) and oxygen (3.64 × 10−13 g·cm·m−1·h−1·Pa−1). The incorporation of natamycin, on the other hand, resulted in films that were more opaque (around 24%) and of a yellowish color. The active nanocomposites developed showed antimicrobial effects against all analyzed fungi and yeasts (approximately 35 mm of inhibition zone) and were able to control the growth of S. cerevisiae in cheese, reducing a log cycle until the 12th day of storage. Since they performed well in vitro and on food, it was concluded that the films showed potential to be applied in Minas cheese preservation.
Milk fat plays an important role in the texture of yogurt. Thus, producing fat-free yogurt is a challenge for the food industry. We investigated and modeled the effect of yogurt composition and process parameters on the texture properties obtained by analyzing the texture profile analysis (TPA) and on the rheological properties. The experiment followed the Box-Behnken (DBB) design with three factors: centrifuge rotational speed (CRS) (3000, 4250 and 5500 rpm), casein (Cas) (3.4, 4.9 and 6.4% p/v) and transglutaminase enzyme (TgE) (0, 1 and 2 U/g of protein) concentrations. A complete second-order model better explained the effect of factors on texture properties. Desirability function was selected for the optimization of responses (firmness, cohesiveness and apparent viscosity placed at a maximum level and adhesiveness, gumminess, thixotropy and loss tangent (tan δ) were placed at a minimum level). The results suggest that the addition of TgE showed less effect on texture properties. The optimized values of each factor, Cas, TgE and CRS were, respectively, 3.4%, 1 U/g of protein and 5500 rpm with general desirability (D) of 0.6531. Under these conditions, it is possible to prepare a concentrated fat-free yogurt with a higher protein content due to the concentration, obtained after centrifugation, as well as obtaining desirable texture characteristics such as greater firmness and consistency, low gumminess and adhesiveness.
Winter beverage formulations made from baru almonds with the addition of sucrose (FS) or allulose (FA) were evaluated in two acceptance sensory sessions (blind test and test with information about the ingredients, their benefits, and the product label) by 100 potential consumers. The beverages were characterized for their proximate composition, pH, soluble solids content, instrumental color, microbiological analyses, steady state rheology, and kinetic stability test. The sensory acceptability of both formulations increased with information provision, reaching an acceptability index exceeding 70%. Furthermore, the sweet taste was the primary driver of acceptance, with consumers generally preferring sucrose as the sweetener. The perception of the sweet taste of FA compared to FS was 67% and 63% in the blind and informed tests, respectively, and showed similar results for physical, chemical, and rheological properties, as well as physical and microbiological stability. Thus, this study underscores the potential of allulose to replace sucrose without significantly altering product characteristics, showcasing its importance from both technological and sensory perspectives. Additionally, the novel product developed with baru contributes to the diversification and valorization of this Brazilian fruit, as well as being a tasty alternative for consumers.