Osmotic dehydration (OD) is a pre-treatment commonly used to incorporate solids and dehydrate fruits. In this study, the influence of mixed syrup (yacon and sucrose) concentration used in OD and ...drying air temperature on drying kinetics of banana osmotically dehydrated and characteristics of dried banana were evaluated. Yacon syrup (30°Brix) was produced and then sucrose was added, making mixed syrups of different concentrations (30–45°Brix). Banana slices (5 mm) were immersed in mixed syrups for five hours. Solid gain (SG) and water loss (WL) were calculated during OD. Afterward, the osmotically dried bananas were dried at different drying air temperatures (40–80 °C). Mathematical models were fitted to the moisture ratio data. The drying rate (DR) was calculated. The dried bananas were evaluated for moisture content, water activity, color and hardness. Optimal treatment was determined using the desirability function. Higher syrup concentration resulted in higher SG and WL during OD. Samples dehydrated osmotically using 32.2°Brix syrup and dried at 74.1 °C required shorter drying time (240 min), with a tendency of higher DR. High syrup concentrations and high temperatures resulted in dried bananas with low water activity and high hardness. The Midilli model was the one that best fitted. The optimal treatment was that using the mixed syrup of 45°Brix and drying temperature of 60 °C.
The objective of this study was to evaluate the acceptability of liqueur based on its sensory profile, physicochemical composition and presence of the volatile compounds responsible for the aroma of ...the banana and banana liqueur. Sensory acceptance was conducted to investigate the effect of alcohol content of the extracting solution on produced liqueurs. In addition, liqueurs were elaborated using different contents of alcohol and sugar, which were evaluated as for pH, soluble solids, refractive index, density, absorbance, colorimetric parameters, besides the sensory analysis to judge the overall impression and the purchase intention of the products. A sensory characterization of the samples was performed by the Optimized Descriptive Profile (ODP) method. The volatile compounds were determined by solid phase microextraction and injected into the gas chromatograph coupled to the mass spectrometer. Adjusted models showed that the alcohol content of 61.87 °GL of the extractive solution and alcohol (17.29 °GL) and sugar (289.89 g L−1) content of the final product may show greater acceptance and intention to purchase banana liqueur. In the ODP, the samples differed based on their adherence, alcoholic aroma, alcoholic taste and sweet taste. Volatile compounds characterized as esters were found on the banana and liqueur.
•The volatile compounds found in banana and liqueurs were characterized as esters.•Alcohol and sugar content influenced the sensorial profile of banana liqueurs.•Six sensorial attributes characterized the banana liqueurs.•The characteristics were influenced by the alcohol and sugar content of liqueur.
The influence of different contents of maltodextrin and whey protein isolate was investigated in the coffee foam, drying kinetics, sensory acceptance of cappuccinos (added of instant coffee) and ...solubility, antioxidant capacity, wettability, and moisture content of dried samples. The desirability function was used to define the optimum process condition. Shorter drying times and greater stability were achieved using higher concentrations of whey proteins than maltodextrin for foams. The results analyzed showed significantly higher retention of bioactive components, low moisture and high wettability of powders. The Midilli model was the most appropriate to represent the drying kinetics. The foaming agents contributed to improving the quality characteristics (aroma, taste, and overall impression) of instant coffee (p < 0.05). There was no influence of the foaming agents on the solubility and density of the powders (p > 0.05). The combination of the agents of 1.32% of maltodextrin and 2.64% of whey protein isolate obtained greater overall desirability (0.6503).
Spent coffee grounds (SCG) are a coproduct that causes environmental impacts worldwide. Thus, consciously reusing the SCG is an eminent need. This work aimed to encapsulate phenolic compounds and ...antioxidants obtained from SCG extracts through spray‐ and freeze‐drying techniques using different isolated and combined wall materials. The dried powders produced were evaluated for moisture content, water activity, bulk density, hygroscopicity, color, content of phenolic compounds and antioxidants, and the results were compared. The results showed that all evaluated treatments resulted in a powdered product with low values of bulk density, moisture and water activity, especially for freeze‐drying. The freeze‐dried product also showed higher hygroscopicity. Regarding the content of phenolic compounds and antioxidants, both drying methods showed high levels of these compounds in the dried product and good encapsulation efficiency, reaching 83.43%. In most cases, spray‐drying and freeze‐drying did not differ statistically (p > 0.05) in relation to bioactive compound content and encapsulation efficiency. In relation to wall materials, albumin showed the worst performance in the retention of bioactive compounds. On the other hand, pure gum arabic combined with maltodextrin led to better preservation of these compounds.
Practical Application
Spent coffee grounds are a coproduct generated in large quantities in the world. The encapsulation of phenolic and antioxidant compounds protects and enables their application in different food matrices. Therefore, the evaluation of different encapsulation methods and wall materials is important to define good process conditions.
Semisynthetic phenol derivatives were obtained from the natural phenols: thymol, carvacrol, eugenol, and guaiacol through catalytic oxychlorination, Williamson synthesis, and aromatic Claisen ...rearrangement. The compounds characterization was carried out by 1H NMR, 13C NMR, and mass spectrometry. The natural phenols and their semisynthetic derivatives were tested for their antimicrobial activity against the bacteria: Staphylococcus aureus, Escherichia coli, Listeria innocua, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, Salmonella enterica ssp. enterica, and Bacillus cereus. Minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values were determined using concentrations from 220 to 3.44 μg mL–1. Most of the tested compounds presented MIC values ≤220 μg mL–1 for all the bacteria used in the assays. The molecular properties of the compounds were computed with the PM6 method. Through principle components analysis, the natural phenols and their semisynthetic derivatives with higher antimicrobial potential were grouped.
Display omitted
•Firmness was variable most affected by irradiation.•Irradiation reduced microbial counts in strawberries.•Irradiated strawberries maintained the same sensory acceptance throughout ...the storage.•Irradiation can be used as a method to increase the shelf life of strawberries.
Consumer demand for food similar to one unprocessed has justified new studies seeking reduced changes in its physicochemical characteristics, the sensory acceptance and the microbiological safety. Irradiation increases the shelf life of foods, according to data in the literature. This study evaluated possible changes during the storage of non-irradiated and irradiated strawberries, the last treated at doses of 1, 2, 3 and 4 kGy, all of them stored at 8 ± 1 °C. The pH, total titratable acidity, ascorbic acid content, weight loss, firmness, the microbiota of natural contaminants and sensory acceptance of strawberries were analyzed. Influence of radiation dose and storage period on the physicochemical characteristics, microbiological quality and sensory acceptance of strawberries were observed. Although control strawberry presented better results for the ascorbic acid content, for firmness and for weight loss, it should be emphasized the effect of irradiation on inactivating mesophilic aerobics and markedly reducing of molds and yeasts. In addition, irradiated strawberries at 2 kGy presented the same hedonic mean on acceptance tests during 12 days of storage. It is suggested to use the 2 kGy dose as an alternative for strawberry conservation, since only minor changes were observed in the product during the 12 days of storage and it was the treatment that obtained better microbiological quality and maintenance of sensory acceptance during the storage period studied. Therefore, irradiation is a method that may be a substitute and could be used along with conventional methods, providing strawberries quality with a longer shelf life.
This study aims to optimize light and dark malt extract production by centrifugal block freeze concentration (CBFC), considering simultaneous optimization of solids concentration (SC), concentration ...efficiency (CE), and concentrate percentage (CP) using a desirability function approach. Two cycles and one recycle of CBFC were evaluated for both malt extracts. A central composite rotational design was employed to predict the effects of freezing temperature (FT) and centrifugal time (t) on malt extract production. The desirability function approach was used for optimization. In scenarios with the highest optimization, operational parameters varied from −29.63 °C to −25.90 °C for FT and 7.00 min to 10.16 min for t. Optimized response values ranged from 2.99°Brix to 26.13°Brix for SC, 69.14% to 86.23% for CE, and 38.30% to 43.86% for CP. The results suggest that optimizing CBFC cycles hinges on liquid mixture properties, and diverse input parameters may be necessary for attaining optimal outcomes.
•Centrifugal block freeze concentration was used for the malt extracts production.•Process parameters were optimized to better performance and efficiency.•Solids concentration increase in the malt extracts ranges from 3.2 to 3.8 times.•Recovered solutions showed 0.8 times the wort's solids concentration.
