Influence of Different Drying Processes on the Chemical and Texture Profile of Cucurbita maxima Pulp.

The effects of hot air (HAD), vacuum (VAD) and conductive (CD) drying on the chemical and textural profiles of Cucurbita maxima pulp were investigated to find suitable drying conditions to avoid postharvest losses of pumpkin. The results showed that the drying methods had a significant effect (p < 0.05) on the chemical and textural profiles of pumpkin pulp. The ash content was lower in VAD (up to 7.65%) than in HAD (up to 9.88%) and CD pulp (up to 9.21%). The samples of HAD, CD and VAD had a higher fat content, up to 3.07, 2.66 and 2.51%, respectively, than fresh pulp (1.55%). The total fibre content is lower for VAD (up to 8.78%) than for HAD (up to 15.43%) and CD pulp (13.94%). HAD pulp at 70 °C (~15.51%) and VAD and CD pulp processed between 50 and 60 °C (~22%) are good sources of protein. HAD and CD pulp at 70 °C and VAD at 50 °C resulted in a high sugar content (up to 83.23%). In addition to drying, the extraction time of 40 min used in ultrasound-assisted extraction is optimal, especially for protein and sugar recovery in dried samples. Drying also led to strong changes in the textural properties of the pulp, so that an excellent dried intermediate product is the one obtained using HAD at a temperature of 70 °C and an airflow of 0.5 m/s.

Influence of Infill Level and Post-Processing on Physical Parameters and Betaine Content of Enriched 3D-Printed Sweet Snacks.

Betaine is a non-essential amino acid with proven functional properties and untapped potential for cereal food enrichment. While 3D printing represents a viable approach for manufacturing enriched cereal-based foods with novel shapes and textures, it is crucial to consider the impact of printing parameters and post-processing on the betaine content and properties of these products. The aim of this study was to investigate the influence of the infill level (20, 30 and 40%) of 3D-printed cuboid shapes and the post-processing techniques (drying oven, vacuum dryer, air fryer) of betaine-enriched oat-based snacks on the print quality, texture, and sensory properties, as well as the content of preserved betaine. The interaction of post-processing technique and infill level influenced the length deviation and texture properties, as well as the betaine content of snacks. Height stability was only influenced by post-processing technique. In general, oven-dried snacks showed the best dimensional stability, having the lowest width/length deformation (about 8%) at the infill level of 20%. Betaine was best preserved (19-31% loss) in snacks post-processed in a vacuum dryer (1281-1497 mg/g), followed by an air fryer and a drying oven, where betaine loss was in the range 28-55%. Air-fried snacks with 40% infill level had the highest values of instrumentally measured crunchiness (38.9 Nmm) as well as sensory test values for liking of texture (7.5), intensity of odor (6) and overall flavor (6). Overall, air frying proved to be a convenient and quick post-processing technique for 3D-printed snacks, but infill patterns for preserving betaine should be further explored. Vacuum drying could be used to preserve bioactive compounds, but efforts should be made to minimize its negative impact on the physical deformations of the 3D-printed products.

Comparison of Drying Methods and Their Effect on the Stability of Grasevina Grape Pomace Biologically Active Compounds.

Valorisation of grape pomace, a by-product of the winery industry, has been pushed into the spotlight in recent years since it can enable lower environmental impact, but it can also bring an added value to the wine production process by recovering several grape pomace biologically active compounds. The first step that allows for grape pomace reuse is its drying, which should be carefully performed in order to preserve the biologically active compounds' stability. In this study, the effects of different drying methods on the stability of polyphenols, tannins and tartaric acid in grape pomace (Vitis vinifera) cv. Grasevina were investigated. In particular, vacuum drying (at different temperatures: 35, 50 and 70 °C), conventional drying at 70 °C and open sun drying were performed and the drying kinetics was described using Peleg's model. Considering the processing time and thermodynamics, vacuum drying at 70 °C was the most convenient processing method. Polyphenols were highly stable during drying, and slight degradation occurred during vacuum drying at 35 and 50 °C. Tannins and tartaric acid were more prone to degradation depending on the drying method applied and showed the greatest stability during vacuum drying at 70 °C.

Non-Thermal Ultrasonic Extraction of Polyphenolic Compounds from Red Wine Lees.

This study presents the results of conventional aqueous (CE) and non-conventional ultrasound-assisted (UAE) extractions of polyphenolic compounds from lees extracts of red wine varieties (Merlot and Vranac). The effect of ultrasound extraction time (t, s), and amplitude (A,%) from a 400 W ultrasound processor with different ultrasonic probes diameters (Ds, mm) on the amount and profile of polyphenolic compounds in the obtained extracts was investigated and compared to CE. The optimal conditions resulting in maximum extraction of phenolic compounds were: Probe diameter of 22 mm, amplitude 90% and extraction time for Vranac wine lees 1500 s and for Merlot wine lees extraction time of 1361 s. UAE proved to be significantly more effective in enhancing the extraction capacity of trans-resveratrol glucoside (30.57% to 300%), trans-resveratrol (36.36% to 45.75%), quercetin (39.94% to 43.83%), kaempferol (65.13% to 72.73%), petunidin-3-glucoside (41.53% to 64.95%), malvidin-3-glucoside (47.63% to 89.17%), malvidin-3-(6-O-acetyl) glucoside (23.84% to 49.74%), and malvidin-3-(6-O-p-coumaroyl) glucoside (26.77% to 34.93%) as compared to CE. Ultrasound reduced the extraction time (2.5-fold) and showed an increase of antioxidant potential by 76.39% (DPPH) and 125.83% (FRAP) compared to CE.

Optimization of High Intensity Ultrasound Treatment of Proso Millet Bran to Improve Physical and Nutritional Quality§.

Millet is an unexploited cereal with potential in the food industry due to its nutritional value and resistance to harsh climate conditions. Nutritious millet byproducts have a potential application in the development of functional cereal products, but require processing in order to improve their physical and nutritional quality. Therefore, we investigated high intensity ultrasound as a pretreatment to increase the amount of freely available bioactives from proso millet bran. We also analysed the effect of high intensity ultrasound on enzymatic browning, water retention and protein digestibility, which are crucial for the utilization in the bakery and pasta industry. A 15% millet bran suspension in water was treated with 400-W ultrasound probe for 5, 12.5 or 20 min, with the 60, 80 or 100% amplitude. High intensity ultrasound treatment with 80% amplitude for 12.5 min improved most significantly the nutritive value; the antioxidant activity measured by FRAP test increased by 15% (p<0.05), and total phenolic content by 16% (p<0.05). Still, the impact on the increase of water-soluble and ethanol-insoluble dietary fibre by 38% was evident after the treatment for 20 min at 100% amplitude. High intensity ultrasound treatment at 100% amplitude for 5 min caused the largest improvements in water retention and limited browning of the sample. High intensity ultrasound treatment activated polyphenol oxidase, regardless of the applied heating of the sample. Due to its ambiguous impact on proso millet bran characteristics, the treatment required an optimization, which showed that the optimal pretreatment of a 15% millet bran suspension in water is at 100% amplitude for 9.3 min.

Effect of ultrasound pre-treatment and drying method on specialized metabolites of honeyberry fruits (Lonicera caerulea var. kamtschatica).

Honeyberries are rich in various nutrients (eg. minerals, and vitamins) and bioactive compounds (eg. polyphenols). The aim of the study was to evaluate the impact of ultrasound (USN) pre-treatment (100% power at 37 kHz) at 40 °C for 3 min and drying techniques (conduction or vacuum) on nutritional composition and bioactive compounds of honeyberry fruits. The evaluation of dried barriers revealed that both USN pre-treatment and drying techniques affected the composition of the final product. The highest vitamin C content (1.067-1.187 mg 100 g-1 DM) was found in fruit samples pre-treated by USN, regardless of the drying technology used. The highest total phenol (2.445 mg GAE 100 g-1 DM), total flavonoid (0.939 mg GAE 100 g-1 DM), total non-flavonoid (1.506 mg GAE 100 g-1 DM) and anthocyanin content (2.334 mg kg-1 FW) were obtained in fruits after applying USN pre-treatment and vacuum dried at 40 °C.

Novel Approach to the Development of Functional Goat's Milk-Based Beverages Using Medicinal Plant Extracts in Combination with High Intensity Ultrasound Treatment.

Regardless of its highly valuable nutritive composition, goat's milk is less preferred by consumers due to its specific sensory characteristics that are very often regarded as undesirable. On the other hand, traditional medicinal plants from Lamiaceae family, due to their rich bioactive composition, especially polyphenols, and desirable aroma profile, can be used to enhance and improve bioactive and sensory properties of food. In the present study nutritively valuable beverages were produced by enrichment of goat's milk with medicinal plant extracts derived from the Lamiaceae family and stabilized by homogenization with high intensity ultrasound treatment. The impact of plant species (lemon balm, mint, lavender, rosemary and sage) and ultrasound treatment duration (5 or 10 min) on the physicochemical, bioactive and sensory characteristics of enriched beverages was evaluated. The addition of plant extracts to goat's milk significantly increased the concentration of bioactive components (rosmarinic acid, hydroxycinnamic acid derivatives and luteolin derivatives), in dependence of the added plant extract. The prolongation of the ultrasound homogenization markedly decreased the fat globule size and thus beneficially affected the product stability. Apart from the achieved bioactive enrichment and stability, the developed beverages exhibited significantly improved sensory properties in comparison to plain goat's milk, with the highest overall acceptability determined for samples enriched with mint and rosemary.

Physical properties and bioactive constituents of powdered mixtures and drinks prepared with cocoa and various sweeteners.

In the present study the physical properties of powdered cocoa drink mixtures prepared from two cocoa powders with various fat contents and different sweeteners, as well as the bioactive content and sensory properties of cocoa drinks prepared from them, were investigated. Particle size and bulk density of the used sugars and sweeteners, as well as the formulated mixtures, were determined and their influence on cohesion index was evaluated. To compare the content of polyphenols in the formulated cocoa drink mixtures, UV-vis spectrophotometric methods were applied. Antioxidant capacity of cocoa drinks was evaluated by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and ferric reducing/antioxidant power (FRAP) assays. The analyzed cocoa drinks prepared from cocoa powder and different sugars or sweeteners delivered a substantial content of cocoa antioxidants, whereas the content and the type of sugar or sweetener did not affect the polyphenolic constituents of the prepared cocoa mixtures. Cocoa powder mixtures prepared with the cocoa powder containing higher fat content (16-18%) generally provided lower total polyphenol, total flavonoid, flavan-3-ol, and proanthocyanidin contents, compared to the mixtures prepared with cocoa containing lower fat content (10-12%). Total phenol content of cocoa drinks prepared from experimental mixtures ranged from 320.45 to 480.45 mg of GAE/L, whereas the ranking of the antioxidant capacities varied depending on the used assay, and the fat content of cocoa powder did not affect the antioxidant capacity of cocoa mixtures. As determined, the addition of sugar to cocoa powder increases the solubility and dispersibility of the mixtures; on the basis of their cohesion index all mixtures can be classified as very cohesive or hardened/extremely cohesive. Results of the sensory evaluation, using the 9-point hedonic scale, showed that there was a preference for the cocoa drinks made with sweeteners (aspartame/acesulfame K and stevia extract), and there was a significant difference in the sensory attributes between the experimental mixtures and the control. The displayed results indicate the significant potential of using alternative sweeteners for the preparation of cocoa drink mixtures, which may provide good physical and sensory properties and also enhance the already existing beneficial effects of cocoa.