Jijun Wu

Quantification and Purification of Mulberry Anthocyanins with Macroporous Resins.

Total anthocyanins in different cultivars of mulberry were measured and a process for the industrial preparation of mulberry anthocyanins as a natural food colorant was studied. In 31 cultivars of mulberry, the total anthocyanins, calculated as cyanidin 3-glucoside, ranged from 147.68 to 2725.46 mg/L juice. Extracting and purifying with macroporous resins was found to be an efficient potential method for the industrial production of mulberry anthocyanins as a food colorant. Of six resins tested, X-5 demonstrated the best adsorbent capability for mulberry anthocyanins (91 mg/mL resin). The adsorption capacity of resins increased with the surface area and the pore radius. Residual mulberry fruit juice after extraction of pigment retained most of its nutrients, except for anthocyanins, and may provide a substrate for further processing.

Comparison of different drying methods on Chinese ginger (Zingiber officinale Roscoe): Changes in volatiles, chemical profile, antioxidant properties, and microstructure.

Nowadays, food industry is facing challenges in preserving better quality of fruit and vegetable products after processing. Recently, many attentions have been drawn to ginger rhizome processing due to its numerous health promoting properties. In our study, ginger rhizome slices were subjected to air-drying (AD), freeze drying (FD), infrared drying (IR), microwave drying (MD) and intermittent microwave & convective drying (IM&CD). Quality attributes of the dried samples were compared in terms of volatile compounds, 6, 8, 10-gingerols, 6-shogaol, antioxidant activities and microstructure. Results showed that AD and IR were good drying methods to preserve volatiles. FD, IR and IM&CD led to higher retention of gingerols, TPC, TFC and better antioxidant activities. However, FD and IR had relative high energy consumption and drying time. Therefore, considering about the quality retention and energy consumption, IM&CD would be very promising for thermo sensitive material.

Effect of ultra-high pressure homogenisation processing on phenolic compounds, antioxidant capacity and anti-glucosidase of mulberry juice

In this study, the effects of ultra-high pressure homogenisation (UHPH) processing at 200 MPa for 1-3 successive passes (inlet temperatures at 4°C) were compared with pasteurisation (95°C, 1 min) processing on phenolic compounds, antioxidant capacity (ORAC value) and anti-glucosidase of mulberry juice. Compared with thermal pasteurisation processing, the more reductions in the anthocyanins, phenolic acids (gallic, protocatechuic, caffeic and p-coumaric acids, and a unknown hydroxycinnamic acid) and quercetin aglycone contents, as well as ORAC value were observed during UHPH processing of mulberry juice, whereas all reductions above during UHPH processing could be inhibited by adding ascorbic acid to mulberry juice. Besides, no significant change (p>0.05) in the α-glucosidase inhibitory activity was observed during UHPH processing of mulberry juice, but showed a 14% reduction in mulberry juice processed by thermal pasteurisation.

Combined Effect of Dimethyl Dicarbonate (DMDC) and Nisin on Indigenous Microorganisms of Litchi Juice and its Microbial shelf life

The individual and combined influences of dimethyl dicarbonate (DMDC) and nisin (200 IU/mL) at mild heat on the inactivation of indigenous microorganisms in litchi juice, including bacteria, molds and yeasts (M&Y), were investigated. The fresh litchi juice with or without nisin were exposed to 250 mg/L DMDC at 30, 40, or 45 °C for 0.5, 1, 2, 3, 4, or 6 h. A complete inactivation of M&Y in the litchi juice with or without nisin was achieved as exposed to 250 mg/L DMDC at 30, 40, or 45 °C for 0.5 h. The bacteria, especially Bacillus sp. and Leuconstoc mesenteroides showed higher resistance than M&Y in the litchi juice. Bacillus sp. and Leuconstoc mesenteroides in the litchi juice was not completely inactivated by 250 mg/L DMDC at 30, 40, or 45 °C. However, nisin addition can enhanced the inactivation of these bacteria by DMDC, and nisin and DMDC also showed a synergistic effect on the inactivation of bacteria. M&Y and bacteria were not detected in the litchi juice added with 200 IU/mL nisin as exposed to 250 mg/L DMDC at 45 °C for 3 h. In addition, microbial shelf life of the litchi juice during storage at 4 °C also was evaluated as treated by 250 mg/L DMDC or combination with nisin at 45 °C for 3 h.

Effect of High Pressure Homogenization and Dimethyl Dicarbonate (DMDC) on Microbial and Physicochemical Qualities of Mulberry Juice.

In this study, the effect of high pressure homogenization (HPH) and dimethyl dicarbonate (DMDC) on microbial and nutrient qualities of mulberry juice was evaluated. Results showed that repeated HPH passes at 200 MPa or adding DMDC at 250 mg/L significantly inactivated the indigenous microorganisms in mulberry juice (P < 0.05), whereas some surviving microorganisms recovered to grow during storage of 4 °C. The combined treatment with 3 passes of HPH and 250 mg/L of DMDC (HPH-DMDC) decreased the population of surviving indigenous microorganisms to the level attained by heat treatment at 95 °C for 1 min (HT) with no significant increase (P > 0.05) in the population of microorganisms during subsequent storage at 4 °C. Moreover, no significant changes (P > 0.05) in the physical attributes, including pH, TSS ((o) Brix), L*, a*, and b* values were observed in the samples treated by the HPH-DMDC or by HT. Compared with HT, HPH-DMDC treatment resulted in a higher degree of retention in total phenolics, and α-glucosidase inhibitory activity, although the treatment led to higher losses in cyanidin 3-glucoside, cyanidin 3-rutinoside, and antioxidant capacity. Overall, HPH-DMDC treatment can be a useful alternative to conventional thermal pasteurization of mulberry juice, considering its ability to inactive, and inhibit indigenous microorganisms.

Chemical Constituents from Roots of Millettia speciosa

Abstract Objective To study the chemical constituents from the roots of Millettia speciosa. Methods The chemical constituents were isolated and purified by silica gel, Sephadex LH-20, and ODS column chromatography. The structures were identified by means of spectral data. Results Fifteen compounds were isolated and identified as naringenin ( 1 ), liquiritigenin ( 2 ), garbanzol ( 3 ), 7-hydroxy-6,4′- dimethoxyisoflavone ( 4 ), calycosin ( 5 ), 2′,5′,7-trihydroxy-4′-methoxyisoflavone ( 6 ), 2′-hydroxybiochanin A ( 7 ), 6-methoxycalopogonium isoflavone A ( 8 ), demethylmedicarpin ( 9 ), 4,4′-dihydroxy-2′-methoxychalcone ( 10 ), 2′,4′-dihydroxy-4-methoxychalcone ( 11 ), rhododendrol ( 12 ), secoisolariciresinol ( 13 ), bisdihydrosiringenin ( 14 ), and polystachyol ( 15 ). Conclusion All compounds are obtained from this plant for the first time.

Slight Fermentation with Lactobacillus fermentium Improves the Taste (Sugar:Acid Ratio) of Citrus (Citrus reticulata cv. chachiensis) Juice.

The aim of this study was to evaluate the hypothesis that fermentation with Lactobacillus fermentium, which can metabolize citric acid, could be applied in improving the taste (sugar:acid ratio) of citrus juice. During fermentation, the strain of L. fermentium can preferentially utilize citric acid of citrus (Citrus reticulata cv. Chachiensis) juice to support the growth without the consumption of sugar. After 6 h of fermentation with L. fermentium at 30 °C, the sugar:acid ratio of citrus juice increased to 22:1 from 12:1, which resulted in that the hedonic scores of sweetness, acidity and overall acceptability of fermented-pasteurized citrus juice were higher than the unfermented-pasteurized citrus juice. Compared with unfermented-pasteurized citrus juice, the ORAC value and total amino acid showed a reduction, and no significant change (P > 0.05) in the L*, a*, b*, total soluble phenolics and ascorbic acid (Vc) content in the fermented-pasteurized citrus juice was observed as compared with unfermented-pasteurized citrus juice. Hence, slight fermentation with L. fermentium can be used for improving the taste (sugar:acid ratio) of citrus juice with the well retaining of quality.

Effects of Dimethyl Dicarbonate (DMDC) on the Fermentation of Litchi Juice by Lactobacillus Casei as an Alternative of Heat Treatment

UNLABELLED This study investigated the effects of dimethyl dicarbonate (DMDC) on the fermentation of litchi juice by Lactobacillus casei as an alternative of heat treatment that may have undesirable effect on the juice. Quality attributes and products stability of both the fermented heat- and DMDC-treated litchi juice by L. casei were compared. It was found that residual indigenous microorganisms in both the heat- and DMDC-treated litchi juice cannot grow into dominant bacteria during further fermentation of litchi juice by L. casei. Compared with fermented heat-treated litchi juice, fermented DMDC-treated litchi juice showed a better color, flavor, and overall acceptance, and also retained more total phenolics and antioxidant capacity. The viability counts of L. casei in both the heat- and DMDC-treated litchi juice were more 8.0 lg CFU/mL after 4 wk of storage at 4 °C. Also, some quality attributes in both the fermented heat- and DMDC-treated litchi juices, including pH, total phenolics, ascorbic acid, antioxidant capacity, and so on, showed the tendency to slow decrease during storage at 4 °C, but the scores of overall acceptance showed no reduction after the storage of 4 wk at 4 °C. On the whole, the application of DMDC treatment could be an ideal alternative of heat treatment to ensure the microbial safety, consistent sensory, and nutritional quality of fermented litchi juice prior to fermentation. PRACTICAL APPLICATION The pasteurization treatment is often recommended prior to fermentation of fruit juice by probiotics, as it would lead to a rapid inactivation and inhibition of spoilage and pathogenic bacteria, and ensure the fermented products with consistent sensory and nutritional quality. Dimethyl dicarbonate (DMDC) is a powerful antimicrobial agent, which was approved for use as a microbial control agent in juice beverages by FDA. This study provides a scientific basis for the application of DMDC prior to fermentation of litchi juice.

Effect of second cooling on the chemical components of essential oils from orange peel (Citrus sinensis).

A second cooling was added to the oil collectors of an improved Clevenger-type apparatus (ICT) to investigate the thermal reaction of essential oils from orange peel compared to a traditional Clevenger-type apparatus (CT). The results demonstrated the yield rate of essential oil from ICT was significantly higher (p < 0.05) than that from CT. The major components of the essential oils consisted of monoterpenes, such as d-limonene, β-myrcene, β-pinene, γ-terpinene, α-pinene. Interestingly, ICT prevented the thermal reaction-the transformation of β-myrcene to β-thujene-and reduced the oxidation on α-pinene and β-pinene of the essential oil in comparison to CT. In addition, the yield rate of γ-terpinene can also be improved via ICT compared to CT. Thus, ICT is an effective improvement to traditional CT.

Inactivation of Escherichia coli and Staphyloccocus aureus in litchi juice by dimethyl dicarbonate (DMDC) combined with nisin.

Inactivation of Gram-negative Escherichia coli and Gram-positive Staphyloccocus aureus in litchi juice by DMDC combined with nisin was individually investigated. A 1.66 log cycles reduction of E. coli and 2.03 log cycles reduction of S. aureus in litchi juice (pH 4.5) added without nisin was achieved as exposed to 150 mg/l DMDC at 30 °C for 1 h, and the inactivation rate of E. coli and S. aureus during initial 1 h was far greater than during the remaining 5 h. As exposed to 150 mg/l DMDC at 30 °C for 1 h, the inactivation of E. coli and S. aureus in the litchi juice showed a trend toward increase with increasing of nisin addition level in the range from 0 to 200 IU/ml. Moreover, DMDC and nisin exhibited a synergistic effect on the inactivation of E. coli and S. aureus in litchi juice, and the inactivation of E. coli and S. aureus in the litchi juice also depends on the temperature of litchi juice, pH value of litchi juice and DMDC concentration when treated with DMDC and nisin. In addition, E. coli showed higher resistance to nisin as comparing with S. aureus. After E. coli and S. aureus in the litchi juice of pH 4.0 were individually treated with 150 mg/l DMDC combined with 200 IU/ml nisin at 30 °C for 1 h, a complete inactivation of S. aureus (6.59 log cycles) was achieved, but only 3.52 log cycles reduction of E. coli was observed.