Yujing Sun

Effects of different factors of ultrasound treatment on the extraction yield of the all-trans-β-carotene from citrus peels

The effects of different factors, including the materials particle size, the extraction solvent, solid/solvent ratio, temperature, extraction time, the electrical acoustic intensity, liquid height and duty cycle of ultrasound exposure on the extraction yield of all-trans-β-carotene from citrus peels by ultrasound-assisted extraction (UAE) were investigated. The extraction yield was significantly affected by particle size. Dichloromethane caused the degradation of all-trans-β-carotene extracted during UAE. Ethanol showed a pronounced higher extraction yield during UAE in comparison with classical extraction (CE). The extraction yield of UAE had a peak value at 25°C. In comparison with classical extraction, the extraction yield of UAE did not easily arrive at equilibrium. The extraction yield increased first, then decreased, then slightly increased with an increase in electrical acoustic intensity. The extraction yield of UAE decreased with increased liquid height. The extraction yield increased with increased duty cycle until equilibrium was achieved.

Phenolic compositions and antioxidant capacities of Chinese wild mandarin (Citrus reticulata Blanco) fruits.

As one of the most important centres of origin for the genus Citrus L., China is rich in wild mandarin germplasm. In this study, phenolic compounds in the peels of 14 wild mandarin genotypes native to China were determined and their antioxidant capacities were evaluated using DPPH, FRAP, ABTS and ORAC methods. We found that Nieduyeju had the highest total phenol content (51.14 mg/g DW), and Wulongsuanju had the highest total flavonoid content (20.66 mg/g DW). Hesperidin, the dominant flavonoid, was observed to be highest in Guangxihongpisuanju (55.98 mg/g DW). Ferulic acid was the most abundant phenolic acid analyzed, and Nieduyeju (7780.17 μg/g DW) and Guangxihongpisuanju (13,607.19 μg/g DW) had the highest contents of extractable and bound phenolic acid, respectively. Antioxidant potency composite (APC) index showed obvious variations ranging from 58.84 to 98.89 in the studied wild mandarins, among them, Nieduyeju had the highest APC index. Overall, Guangxihongpisuanju, Nieduyeju, Cupigoushigan and Daoxianyeju contained more phenolics and exhibited higher antioxidant capacities than the mandarin cultivars Satsuma and Ponkan.

Stability of all-trans-β-carotene under ultrasound treatment in a model system: Effects of different factors, kinetics and newly formed compounds

The effects of factors and kinetics of all-trans-beta-carotene degradation under ultrasound treatment in a model system were investigated. The compounds of degradation were also tentatively identified by HPLC-DAD, Raman and FT-IR spectroscopy. The type of solvents and temperature were important factors in determining the degradation reaction. Liquid height, ultrasonic intensity and duty cycle of ultrasound exposure only affected the rate of degradation but did not change the nature of degradation. Degradation rate of beta-carotene in dichloromethane was the highest. Degradation rate of beta-carotene decreased with increasing of temperature. Degradation kinetics of all-trans-beta-carotene under ultrasound fitted first-order reaction at -5 to 15 degrees C, and fitted second-order reaction at 25 degrees C. Degradation products included isomers: 15-cis-beta-carotene, di-cis-beta-carotene and other compounds with function group of C-O.

In vitro digestion combined with cellular assay to determine the antioxidant activity in Chinese bayberry (Myrica rubra Sieb. et Zucc.) fruits: A comparison with traditional methods

The traditional method of chemical extraction (i.e., extracts), combined with chemical antioxidant activity assays cannot assess the real antioxidant activity. In vitro digestion (i.e., digesta) with a cellular antioxidant activity (CAA) assay was developed for the determination of antioxidant activity in Chinese bayberry fruits. In this study, pretreatment methods were studied and the results showed that digesta had more free phenolic acids (FPA) but less total phenolic content (TPC) and total anthocyanin content (TAC) than extracts. Antioxidant activity assays, including ABTS, FRAP, DPPH, ORAC and CAA, were compared. Digesta had lower ABTS, FRAP and DPPH values but higher CAA values than extracts. FPA were better correlated with the chemical antioxidant assays in digesta. The correlations were high between TPC and CAA values in digesta (R(2)=0.96) but not extracts (R(2)=0.58). Higher correlations were also obtained between CAA and chemical assays in digesta.

Phytochemical Profile and Antioxidant Activity of Physiological Drop of Citrus Fruits

UNLABELLED The phytochemical content and the antioxidant activity (AA) of physiological drop of the main citrus species grown in China were investigated. Among the flavonoids, hesperidin was found mostly in mandarin and sweet orange, naringin was found mostly in sour orange, pummelo, grapefruit and a hybrid (Gaocheng), narirutin was found in most varieties, neohesperidin was found in Gaocheng and Huyou, and nobiletin and tangeretin were found in most varieties. Hydroxycinnamic acids were the main phenolic acids present, ferulic acid and caffeic acid were the dominant in most cases. There was a greater amount of free (extractable) than bound (insoluble) phenolic acids. Levels of limonoids were higher in Foyou, Eureka lemon, and Gaocheng than those in the other cultivars. The highest level of synephrine was found in Ponkan and Weizhang Satsuma. AA was highest in Ponkan and Weizhang Satsuma and lowest in Huyou, pummel, and lemon. These results suggest that physiological drop of citrus fruits have good potential as sources of different bioactive compounds and antioxidants. PRACTICAL APPLICATION Physiological drop of citrus fruits may be a good resource of bioactive compounds including flavonoids, phenolic acids, limonoids, synephrine, and a good material of nutraceuticals.

Depolymerization of fucosylated chondroitin sulfate from sea cucumber, Pearsonothuria graeffei, via 60Co irradiation.

A method for depolymerization of a novel fucosylated chondroitin sulfate from Pearsonothuria graeffei (fCS-Pg) using (60)Co irradiation in water solution was developed in the current study. Fragments with varying molecular weights were obtained by (60)Co irradiation at different dosages and sample concentrations. The chemical compositions and structures of these fragments were further investigated using high-performance liquid chromatography (HPLC), infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). Our results indicated that (60)Co irradiation induced depolymerization via selective breakage of glucuronic acid units in the fCS-Pg backbone, with no obvious influence on sulfated fucose branches under mild conditions. The recommended conditions for fCS-Pg degradation were 2-10% solution concentration and irradiation dosages of 10-50kGy. The anticoagulant activities of the low molecular weight fragments were additionally evaluated. Notably, anticoagulant activities were reduced with decreasing molecular weights. Compared to the native fCS-Pg, low molecular weight fragments displayed significantly decreased anticoagulant activities. Based on the collective findings, we propose that these fragments are potentially applicable as antithrombotic agents with reduced bleeding risk relative to native fCS-Pg.

Ultrasound effects on the degradation kinetics, structure, and antioxidant activity of sea cucumber fucoidan.

The effects of ultrasound on the molecular weight, structure, and antioxidant potential of a fucoidan found in Isostichopus badionotus were investigated. The results showed the molecular weight (Mw) of fucoidan decreased obviously after ultrasound treatment. Higher ultrasonic intensity, lower temperature, and lower fucoidan concentrations led to a more effective sonochemical effect. The kinetic model for fucoidan degradation fitted to 1/M(wt)-1/M(w0) = kt at the tested temperature. The optimized degradation conditions by response surface methodology (RSM) were temperature, 12 °C, and intensity, 508 W/cm². Structural analysis by FTIR and NMR indicated the fucoidan kept the linear tetrasaccharide repeating units as the original polysaccharides after the ultrasound treatment, with only slight destruction of the middle nonsulfated fucose units. Antioxidant activity assay showed the antioxidant activity was slightly improved by the ultrasound treatment. The results suggested that ultrasound treatment is an effective approach to decrease the M(w) of fucoidan with only minor structural destruction.

Sonochemical effects on free phenolic acids under ultrasound treatment in a model system.

Sonochemical effects on seven free phenolic acids under ultrasound treatment in a model system have been investigated. The degradation products have also been tentatively identified by FTIR and HPLC-UV-ESIMS. Five phenolic acids (protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, p-coumaric acid, and ferulic acid) proved to be stable, while two others (caffeic acid and sinapic acid) were degraded under ultrasound treatment. The nature of the solvent and the temperature has been identified as important factors in determining the degradation reaction. Liquid height, ultrasonic intensity, and duty cycle of the ultrasound exposure affected only the degradation rate and did not change the nature of the degradation. The degradation rates of caffeic acid and sinapic acid decreased with increasing temperature. The degradation kinetics of these two acids under ultrasound conformed to zeroth-order reactions at -5 to 25 °C. Both decomposition and polymerization reactions occurred when caffeic acid and sinapic acid were subjected to ultrasound. Degradation products, such as the corresponding decarboxylation products and their dimers, have been tentatively identified.

Influence of hot water dip on fruit quality, phenolic compounds and antioxidant capacity of Satsuma mandarin during storage.

The influence of hot water dips (50, 52 and 54 ℃ for 3 min) on fruit quality, phenolic compounds and antioxidant capacity of Satsuma mandarin during 60 days’ storage at 10 ℃ was investigated. Hot water dips did not affect fruit quality attributes as well as ascorbic acid content, and 50 ℃ treatment significantly reduced fruit weight loss. Significant increases of flavonoids were found in all hot water treated fruit from after treatments till 15 days of storage, whereas phenolic acids were not greatly affected. Hot water dipping at 50 ℃ significantly increased total phenolics and antioxidant capacity of Satsuma mandarin immediately after treatment and maintained similar levels with control during storage, while 52 and 54 ℃ treatments showed relatively lower levels. The results suggested that hot water dipping at 50 ℃ for 3 min can be a promising way to retain functional quality of storing Satsuma mandarin.

The Sonodegradation of Caffeic Acid under Ultrasound Treatment: Relation to Stability

The degradation of caffeic acid under ultrasound treatment in a model system was investigated. The type of solvent and temperature were important factors in determining the outcome of the degradation reactions. Liquid height, ultrasonic intensity and duty cycle only affected degradation rate, but did not change the nature of the degradation. The degradation rate of caffeic acid decreased with increasing temperature. Degradation kinetics of caffeic acid under ultrasound fitted a zero-order reaction from −5 to 25 °C. Caffeic acid underwent decomposition and oligomerization reactions under ultrasound. The degradation products were tentatively identified by FT-IR and HPLC-UV-ESIMS to include the corresponding decarboxylation products and their dimers.