Alteration of Bioactive Compounds and Antioxidative Properties in Thermal, Ultra-High Pressure and Ultrasound Treated Maoberry (Antidesma Bunius L.) Juice during Refrigerated Storage

Maoberry (Antidesma bunius L.) is a tropical fruit locally referred to as “Mao-Luang” in Thailand. The fruit contains high amounts of ascorbic acid and phenolic compounds with antioxidative potential, which has demonstrated medicinal value in terms of anti-cancer and anti-diabetic effects. In this term, this research purposed to determine the changes of predominant bioactive phytochemicals, antioxidant capacity and microbiological quality of pasteurized (85ºC/1 min), pressurized (500 and 600 MPa/30ºC/30 min), and ultra-sonicated (20 kHz/60% and 80% amplitude/30 min) maoberry juices during storage at 4°C for 30 days. The results displayed that ascorbic acid, phenolic acids (gallic and vanillic acids), anthocyanins (cyanidin 3-o-glucoside and cyanidin 3-rutinoside), flavonoids [(+)-catechin and (˗)-epicatechin), 2,2-diphenyl-1-picryl hydrazyl hydrate (DPPH) radical inhibition and ferric reducing antioxidant power (FRAP) value in pressurized and ultra-sonicated juices displayed higher reduction rate during storage than those in pasteurized juice. Nevertheless, at the final stage of storage, both juices still contained higher levels of antioxidant compounds and properties than in thermally treated juice. All the treated samples were shown to reduce initial microbial load of fresh maoberry juice to a non-detectable amount, while maintaining their quality during prolonged refrigerated storage.

Ultrasonication of Thawed Huyou Juice: Effects on Cloud Stability, Physicochemical Properties and Bioactive Compounds

In order to remove the flocculent precipitation in Huyou juice after frozen storage and thawing process, the thawed juice was ultrasonically treated with different power (45-360 W) and time (10-60 min) in ice bath (~0 °C), and its sedimentation behavior during storage was observed. After optimization, the cloud stability of juice could be improved by ultrasonic treatment with ultrasonic power of 360 W or more for at least 30 min, which could be stable during 7 days of storage at 4 °C. Under this optimal condition (360 W, 30 min), the effects of ultrasound on the physicochemical properties and bioactive compounds of thawed Huyou juice during storage were investigated. The results showed that with smaller particle size and lower polymer dispersity index, ultrasonic treatment did not significantly change the color, soluble solids, titratable acidity, and bioactive compounds including flavonoids and other phenolics. In addition, all properties of samples were at the same level during storage. Thus, ultrasound was applicable since it can improve the cloud stability of Huyou juice with minimal impact on its physicochemical properties and nutritional quality compared to the untreated one.

Effect of Ultrasonic Assisted Extraction on the Properties of Freeze-Dried Pomegranate Arils

Background:

All parts of the pomegranate (fruits, leaves, flowers, and roots) are traditionally used as a folk medicine due to its high antioxidant and phenolic property. The pomegranate fruit is known for its antimicrobial, anticancer and anti-arteriosclerotic properties.

Objective:

The current study aims to the effect of ultra-sonication and temperature (45°C) on freezedried pomegranate arils powder for extraction of phenolic and flavonoid compounds and to study the antioxidant activity.

Methods:

The freeze-dried arils of pomegranate (Ganesh variety) were procured and subjected to ultra- sonication methods at 45ºC applied for 30 minutes by using methanol, ethanol, water, acetone and hexane solvent for obtaining the extract. The methanolic extract showed the highest phenolic (3036.725 ± 5.39 Gallic acid equivalents mg/100gm), flavonoid (15882.088 ± 0.64, quercetin mg/100g), antioxidant activity (96.1367±0.13%) and free reducing antioxidant power (FRAP assay-18.9033 ± 0.12, Tor. mg/100 ml) respectively, as compared to the extract obtained through other solvents.

Results:

The results obtained indicate that the freeze-drying method and ultrasonic extraction method is one of the effective and quick methods for quality extraction of phenolic and flavonoids compounds from fruits.

Conclusion:

The technology can further be explored for the development of nutraceutical and health supplements.

Ultrasound-Assisted Optimal Development and Characterization of Stevia-Sweetened Functional Beverage

Nowadays, blend of different fruit juices as functional beverages is highly recommended to retain maximum concentration of nutrients due to their integrated effect against processing, to utilize underconsumed fruits and/or vegetables, and to provide healthy product to the consumer. The novelty in this particular work is optimization of blend using stevia-based low caloric extract as sweetener to replace high caloric sugar contents. For this purpose, juices of apple and carrot along with the extract of stevia leaves underwent the process optimization using a statistical approach of D-optimal mixture design. The best beverage formulation with high sensory scores was composed of apple juice 70%, carrot juice 27%, and stevia extract (5 g/100 ml) 3%. The optimized beverage was then processed with conventional pasteurization at 95°C for 1 min and compared with ultrasound processing for 15 min at four different amplitudes (20%, 40%, 60%, and 80%). According to the observation, the treatment US60 (60% amplitude for 15 min) showed better retention for total phenolic content (78.65 ± 1.37 mg GAE/100 mL), total flavonoid content (23.53 ± 0.15 mg CE/100 mL), DPPH (66.43 ± 1.45 %), and FRAP (65.17 ± 1.10 mmol Trolox/100 mL) as compared to pasteurized and control samples while keeping other physicochemical properties in range. The research therefore indicates that ultrasound is good alternative to pasteurization and stevia to sugar in terms of functional beverage development.