Bread shelf life remains a major challenge for the bakery industry, particularly in clean-label products produced without chemical preservatives. In this context, sourdough fermentation has emerged as a promising strategy to improve bread quality and stability. This study evaluated the technological potential of kefir whey as a sourdough starter material for breadmaking, comparing its performance with those of traditional sourdough (TS) and baker's yeast-based sponge (BY). The resulting breads were characterized regarding fermentation performance, physicochemical properties, sensory acceptance, and shelf life. Kefir sourdough (KS) exhibited a slower dough expansion rate than TS and BY, requiring a longer fermentation period. Nevertheless, sourdough breads (KS and TS) showed higher acidity, a firmer texture, and lighter crust coloration than BY breads, while crumb coloration was darker in KS and TS than in BY. The higher acidity was associated with delayed visible mold growth under the tested storage conditions, with KS and TS breads showing approximately 40% and 70% longer shelf life, respectively, compared with BY bread. Despite the firmer texture, KS and TS breads showed only slight reductions in specific volume (5%–9%) and no significant differences in crumb porosity compared with BY breads. Sensory analysis revealed lower preference scores for TS bread, whereas KS bread showed acceptance and preference comparable to BY bread. These findings suggest that kefir whey has promising potential as a sourdough starter material for breadmaking, allowing the production of breads with extended shelf life and good consumer acceptance, and pointing towards possible applications for the valorization of this kefir-derived fraction.
The impact of replacing animal fat with tiger nut ( Cyperus esculentus ) flour (TNF) on the bioactivity and quality attributes of beef burgers was evaluated during refrigerated storage for 6 days. The control formulation consisted of 85% meat and 15% animal fat. The animal fat part was replaced with TNF at levels of 0%TNF (T1), 5%TNF (T2), 10%TNF (T3), and 15%TNF (T4). In addition to enhancing dietary fiber content, incorporation of TNF significantly ( P -value ≤.05) increased total phenolic content and antioxidant activity, as determined by the Folin–Ciocalteu and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays respectively. Lipid oxidation was markedly reduced in TNF-treated samples during storage, as reflected by lower peroxide and thiobarbituric acid reactive substances (TBARS) values. After 6 days, T4 exhibited the lowest peroxide value (2.60 meq O 2 /kg fat) and TBARS value (0.47 mg MDA/kg fat) compared with the control T1 (4.88 meq O 2 /kg fat and 0.94 mg MDA/kg fat, respectively). Microbiological analysis indicated improved microbial quality in burgers containing TNF. Texture profile analysis showed that firmness, cohesiveness, gumminess, chewiness, and springiness of produced beef burgers increased with TNF addition. Moreover, TNF reduced cooking loss by 25%, from 42% in T1 to 17.34% in T4. Sensory evaluation revealed that sample T2 was the most preferred formulation.
The thermal processing of tomato ( Solanum lycopersicum L. ), both at home and commercially, is key for obtaining derivatives, such as preserves, sauces, pastes, and purees, consumed worldwide. Therefore, in this study, the effects of different heat treatments, such as frying, blanching, and cooking, on the physicochemical parameters and antioxidant properties of yellow plum tomato ( S. lycopersicum L., var. Blondkopfchen ) were evaluated. The conditions used were frying in vegetable oil (150 ± 5 °C, 3 min), blanching in water (90 ± 2 °C, 5 min), and cooking in water (95 ± 2 °C, 10 min) compared to fresh fruit. Heat treatments showed significant differences ( p < 0.05) in physicochemical and antioxidant properties compared to fresh tomatoes. Regarding color, increases in the yellowness index were observed in all heat treatments. Frying resulted in the highest total carotenoid content (3.35 mg/100 g), and antioxidant activity (AA) [15.52 mmol Fe + 2 /100 g and 46.59% 2,2-diphenyl-1-picrylhydrazyl (DPPH)] compared to the fresh sample, which had values of 2.07 mg/100 g, 9.63 mmol Fe + 2 /100 g, and 32.24% DPPH, respectively. Blanching resulted in the lowest loss of total phenolic content (8.34 mg GAE/100 g) compared to the other methods, while cooking resulted in the lowest loss of vitamin C (48.58 mg/100 g) compared to the other methods. It can be concluded that frying is the best treatment for increasing the ash, ether extract, total carotenoid content, and AA content in plum tomatoes compared to the other methods. Blanching and cooking allow for a higher concentration of preservation of total phenolic compounds and vitamin C compared to frying. This information is relevant for optimizing production processes and promoting the use of this little studied variety in the food industry.
Foam layer drying is an alternative to conventional dehydration methods due to its ability to reduce thermal damage and preserve bioactive compounds of different food matrices. This study aimed to evaluate the physical, chemical, and microbiological characteristics of tropical fruit powders (watermelon, guava, pineapple, and acerola) obtained by foam layer drying using a combined system of powdered egg white albumin and carboxymethylcellulose. The fruit pulps were processed, foamed, and dried at 68 °C for 6 h, and the resulting powders were characterized in terms of hygroscopicity, density, flowability, water and oil retention capacity, color, moisture, water activity, phenolic and carotenoid compound profiles, antioxidant capacity, microbiological quality, and antimicrobial activity. The powders showed low moisture (2.8–3.6%) and water activity (0.18–0.22), excellent flowability, low hygroscopicity (1.28–3.66%), and favorable functional properties. High levels of phenolic and carotenoid compounds were preserved, resulting in pronounced antioxidant activity. All samples met the microbiological standards stipulated in the legislation, showing an absence of pathogenic bacteria and low microbial counts. Limited and selective antimicrobial activity was observed in the hydroethanolic extracts. Overall, foam drying proved to be an efficient and robust technology for the production of tropical fruit powders rich in bioactive compounds, with great potential for application as functional ingredients.
Milk beer originated in China and is a widely popular refreshing dairy beverage. Its distinctive flavor primarily stems from Kluyveromyces marxianus used during fermentation. However, the current high-density fermentation process for this yeast strain remains constrained by a dry weight yield of 70 g/L, coupled with relatively high production costs. These factors limit the application of yeast in the production of milk beer. This study aims to establish a high-density cultivation process and feeding regimen for Kluyveromyces marxianus to enhance its viable cell count and dry weight, thereby evaluating its applicability in milk beer production. First, the optimal cultivation conditions for the Kluyveromyces marxianus MK5 strain were determined in a 5 L fermenter, which was then used for fed-batch fermentation. Subsequently, the resulting milk beer was compared with milk beer produced using the commonly used Kluyveromyces marxianus MJ strain and a blank acidified milk solution. Results indicated that simulated exponential fed-batch fermentation at a specific growth rate of 0.05 h −1 significantly promoted MK5 growth. The maximum viable cell count reached 1.88 × 10 10 colony-forming unit/mL during cultivation, with a dry cell weight of 113.7 g/L. Furthermore, milk beer samples fermented with strain MK5 demonstrated significant advantages in enhancing milk beer stability and improving flavor.
