Filters
Impregnacja próżniowa wspomagana ultradźwiękami - ocena wpływu ultradźwięków na efektywność procesu nasycania materiałów roślinnych oraz ich właściwości
Chokeberry Pomace Utilization for Improving Selected Quality Parameters of Green Tea Leaves or Hibiscus Flower Infusions
The utilization of food industrial by-products, especially pomace after juice processing, could be a big challenge. Chokeberry pomace is a valuable source of phenolic compounds, including procyanidins and anthocyanins. These compounds have, e.g., antioxidant, anticancer, hypoglycemic, hypotensive, hepatoprotective and cardioprotective effects. In this work, dried chokeberry pomace (2.0 g, 2.5 g and 3.0 g) was added to green tea leaves or white or red hibiscus flowers (0.5 g of each) to obtain mixtures for preparing infusions. Such products could be a valuable source of bioactive compounds. After brewing and cooling, selected quality parameters of the obtained infusions were tested: pH, total phenolic content (TPC), anthocyanin content and the instrumentally and sensorily determined color. The composition of the infusion had an impact on the color. Those from a mixture of chokeberry by-products and hibiscus possessed lower L* and higher a* and b* values than those composed of chokeberry and green tea leaves. Infusions prepared from the mixture containing dried chokeberry pomace (3.0 g) and green tea leaves (0.5 g) had a higher content of anthocyanins (17%) and phenols (48%), respectively, than other samples with the same proportions of ingredients. According to PCA analysis, the highest content of the tested bioactive compounds was obtained in infusions of green tea leaves with the addition of chokeberry pomace.
Suitability of Apples Flesh from Different Cultivars for Vacuum Impregnation Process
The article evaluated the suitability of 14 apple cultivars for the vacuum impregnation (VI) process based on the comparison of the physicochemical properties of fresh and impregnated tissue. The cube-cut apple was impregnated in a solution close to isotonic composed of 0.5% ascorbic acid, 0.5% citric acid, and 10% sucrose. The VI process was conducted with vacuum time and absolute pressure at 10 min and 15 kPa, restoring atmospheric pressure at 5 min and relaxation time at atmospheric pressure at 10 min. The content of ascorbic acid after VI increased by 3 to 25 times and was in the range of 73.5–130 mg/100 g, while the mass gain for the samples ranged from 15% to 34%. On the basis of the Pearson correlation, it was found that the mass gain was negatively correlated with the firmness of the fresh apple cubes (r = −0.85). The cultivars with favorable features after the VI process in terms of vitamin C content; hardness; and browning index (BI) are Cortland; Shampion; and Ligol.
The Effect of the Cultivar and Process Parameters on Quality and Biologically Active Compounds Content in Impregnated Carrot Tissue
Vacuum impregnation (VI) allows soluble solids to be introduced into the porous matrix of a food material, modifying the composition of the tissue to facilitate further processing. The purpose of this research was to analyze the influence of pressure on the effectiveness of VI on a low porous material that is difficult to impregnate. Two cultivars of carrot (Baltimore F1 and Komarno) were subjected to VI at 5 and 30 kPa in a ternary solution of ascorbic acid (0.5%), citric acid (0.5%), and sucrose (8%) under isotonic conditions. The products were analyzed in terms of ascorbic acid content, degree of impregnation, and changes in structure, texture, color, antioxidant activity, phenolic content, carotenoids, and structure-forming compounds. Increases in vitamin C content (after VI) depended on the process conditions and ranged from 900% to 1300% in relation to the raw material. It was also observed that the extended impregnation time at a pressure of 5 kPa produced slices that were also impregnated in parenchyma area. The increased levels of polyphenolic compounds found in the saturated product may suggest that de novo synthesis under the influence of physiological stress had occurred.
Sustainable Use of By-Products (Okara and Linseed Cake) in Tempeh Fermentation: Effects on Isoflavones and Lignans
Okara and linseed cake are nutrient-rich by-products containing phytoestrogens, which are underutilized in food production. The aim of this study was to optimize hydrothermal treatment and fermentation time using common starters for tempeh fermentation. Changes in isoflavones and secoisolariciresinol diglucoside (SDG) were analyzed using the HPLC-PDA method. Okara and linseed cake were steamed for 5 to 40 min, followed by fermentation with Rhizopus oligosporus at 30 °C for 48 h. The optimal steaming times were 10 min for okara and 20 min for linseed cake. Isoflavone analysis revealed a change in total levels depending on the microflora, with a significant increase in aglycones during fermentation. SDG levels did not show a significant reduction. In 24-h fermented tempeh, the isoflavone acetylglycosides content increased after frying. These results suggest that steam treatment is an effective hydrothermal method, offering energy and water savings. Additionally, the ability to modulate isoflavone composition through fermentation creates new opportunities for pro-healthy food development. This study concludes that okara and linseed cake can be successfully used for tempeh production, providing a sustainable alternative to conventional tempeh substrates. By utilizing these by-products, this research promotes the reduction of food waste and supports the development of environmentally friendly food production practices.
Sposób wytwarzania kostki jabłkowej w żelu z wykorzystaniem procesu nasączania próżniowego oraz sytemu pakowania typu bag in box
Effect of refining and fractionation processes on minor components, fatty acids, antioxidant and antimicrobial activities of shea butter
Shea butter is becoming increasingly popular in foods, cosmetics and pharmaceutical products. This work aims to study the effect of the refining process on the quality and stability of fractionated and mixed shea butters. Crude shea butter, refined shea stearin, olein and their mixture (1:1 w/w) were analyzed for fatty acids, triacylglycerol composition, peroxide value (PV), free fatty acids (FFA), phenolic (TPC), flavonoid (TFC), unsaponifiable matter (USM), tocopherol and phytosterol content. Additionally, the oxidative stability, radical scavenging activity (RSA), antibacterial and antifungal activities were evaluated. The two main fatty acids in the shea butter samples were stearic and oleic. The refined shea stearin showed lower PV, FFA, USM, TPC, TFC, RSA, tocopherol and sterol content than crude shea butter. A higher EC50 was observed, but antibacterial activity was much lower. The refined olein fraction was characterized by lower PV, FFA and TFC in comparison with crude shea butter, but USM, TPC, RSA, EC50, tocopherol and sterol content was unchanged. The antibacterial activity was higher, but the antifungal activity was lower than those of crude shea butter. When both fractions were mixed, their fatty acid and triacylglycerol composition were similar to those of crude shea butter, but other parameters were different.
Zżelowany produkt oparty na przecierze z odpadów po mechanicznym obieraniu jabłek oraz sposób jego wytwarzania
The Effect of Ultrasound and Lactic Acid Fermentation on the Selected Quality Parameters and Bioactive Compounds Content in Fermented Pumpkin (Cucurbita pepo L.)
Increasing the consumption of fruit and vegetables can be achieved by creating new products. A promising method seems to be the directed fermentation of vegetables. The aim of this study was to investigate the effect of ultrasonic pretreatment (US; 25 kHz; 5 min) and the lactic acid bacteria strain (LAB; Lactiplantibacillus plantarum 299v and Lacticaseibacillus rhamnosus GG) on the quality of fermented pumpkin (Cucurbita pepo L.). The pumpkin was inoculated with 5 log CFU/g of specific LAB strain. Fermentation was carried out for 7 days at 35 °C. Some samples were US treated at the washing stage. During fermentation, there was an increase in the LAB count of 3 logarithmic cycles compared to the initial inoculum. For L. rhamnosus, preceding fermentation by US treatment contributed to an increased bacteria count of 4 logarithmic cycles. In the case of fermentation with L. rhamnosus, the lactic acid content was significantly higher than for L. plantarum. These samples are also characterized by higher sensory properties, desirability of taste, and overall desirability. Fermentation contributed to a decrease in carotenoid and phenolic compounds content and an increase in the antioxidant capacity of the pumpkins, regardless of the bacterial strain.
Application of Chia and Flaxseed Meal as an Ingredient of Fermented Vegetable-Based Spreads to Design Their Nutritional Composition and Sensory Quality
Fermented vegetable spreads could offer an opportunity to diversify the range of plant-based foods. The challenge in developing the spreads is to achieve high quality, including stable consistency, consumer desirability and high nutritional value. The aim was to evaluate the application of chia and flaxseed meal for fermented zucchini-cucumber spread production. The effect on the chemical composition, phenolic compound content, antioxidant activity, and sensory quality of the vegetable spread was evaluated. Its color, viscosity, and microstructure were also analyzed using instrumental methods. The meal addition varied from 4.0 to 14.0%. The spread with meal addition had higher fat, protein, ash, and dietary fiber content than the control. Total free phenolic compound content and antioxidant activity also increased, and chia seed meal impacted the parameters more. On the contrary, flaxseed meal improved more the product’s consumer desirability than chia. Both were effective gelling agents that increased viscosity and enhanced product spreadability, and only flaxseed meal showed a masking ability. Its addition reduced the perception and intensity of the bitter, tart, and sour taste. The spread formula consisting of fermented zucchini and cucumber with 9 to 11.5% flaxseed meal addition was the most recommended to achieve the product with high consumer desirability.
Effect of ultrasonic, thermal and enzymatic treatment of mash on yield and content of bioactive compounds in strawberry juice
Strawberries are rich in bioactive compounds that may be of health importance. The technological process often significantly reduces the content of such compounds in the product. The study aimed to compare the effect of enzymatic, ultrasonic and thermal mash treatment on the content of ascorbic acid, anthocyanins, phenolic compounds and the antioxidant activity of strawberry juice. In addition, the effect of increased temperature assisting ultrasonic mash treatment and the use of a vacuum for a short period to remove air from the mash during pectinolysis was investigated. A significant increase in the efficiency of juice pressing was obtained for enzymatic treatment (by 40%), thermal and thermosonication (16%). It was found that the applied methods yield different results depending on the tested compounds. In the case of anthocyanin, the most effective method was thermosonication, which contributed to a 40% increase in their content. The enzymatic and thermal methods resulted in a two-fold increase in the content of phenolic compounds. The antioxidant activity of the juice from the treated mash (regardless of the method used) was significantly higher than samples from the untreated mash. A significant correlation (r = 0.77) was noted between antioxidant capacity and non-anthocyanin phenolic compound content in the tested juices.