Antioxidant and antimicrobial activities of the methanol extracts from pummelo (Citrus grandis Osbeck) fruit albedo tissues

The present study was conducted to evaluate the antioxidant and antimicrobial properties of methanol (100 and 80% aqueous) extracts of pummelo fruits albedo (Citrus grandis Osbeck). The antioxidant and antibacterial activity for crude extracts and isolated compounds were evaluated using free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Paper disc diffusion method. A 100% Methanol (MeOH) extract was steeped in water at different pH levels and partitioned with ethyl acetate (EtOAc) to give basic, acidic, neutral, and phenolic fractions. The neutral extract was found to possess maximum antioxidant and antibacterial activity. Thereafter, neutral extract was carried out on a silica gel column and eluted with hexane:EtOAc:acetone and preparative TLC (PTLC) to give oil buntan compound, linoleic acid methyl ester, β-sitosterol, sigmasterol, limonin, nomilin and meranzin hydrate were isolated. While, 80% MeOH extract was fractionated also using a silica gel column and PTLC to give isomeranzin hydrate, p-coumaric acid and caffeic acid compound. The extract concentration providing 50% inhibition (IC₅₀) was as follows; oil buntan compound 95 μg/mL, caffeic acid 45 μg/mL, p-coumaric acid 105 μg/mL, limonin + nomilin (mixture) 135 μg/mL was lower than that of synthetic antioxidant butylated hydroxyanisole (BHA) 40 μg/mL. The inhibitory zone (mm) of bacteria tested was 2.9–4.1 mm caffeic acid and 11.6–15.1 mm p-coumaric acid.     

果胶酶在猕猴桃果汁处理中的应用

研究了采用果胶酶HC澄清猕猴桃果汁时的工艺条件和在猕猴桃果浆榨汗中的应用，并通过实验得出结论，澄清时，酶HC加量40mg/L,pH3-4，温度40－50℃，处理150min，用此处理工艺所得猕猴桃汁的Vc损失较小，透光率较高，果胶基本分解完全在果浆榨汁中，也只需采用相同的用量就能使果汁的粘度下降71％，出汁率提高10％以上，而营养物质基本无损耗。     

果胶裂解酶--果蔬汁加工行业的一次新技术革命

果胶酶XXL系列强有力的果胶酶活力和经济有效的副活性,不但可以迅速降解果胶成分,而且可以有效控制水解产物,满足国际质量检测要求。XXL系列产品在各种果蔬清汁和浊汁生产中的成功应用,形成了果蔬汁加工行业的一次技术革命。     

Inoculated fermentation of orange juice (Citrus sinensis L.) for production of a citric fruit spirit

The yeast Saccharomyces cerevisiae UFLA CA1174 was evaluated for its potential to produce an orange spirit, as a possible alternative to reduce waste and increase income to citrus farmers. The sugar concentration of the orange juice was adjusted to 16ºBrix and the pH to 4.5. The orange juice was inoculated at approximately 7 log CFU/mL, and the fermentation was performed at room temperature until ºBrix stabilization. The yeast used showed high values for the conversion factors of the substrates into ethanol (Y_p/s 0.50 g/g), the volumetric productivity of ethanol (Q_p 1.78 g/L/h), the biomass productivity (P_x 58.47 g/g) and the fermentation efficiency (E_f 97.83%). The sugars were converted quickly, and a high ethanol concentration (58.13 g/L) was achieved after 24 h of fermentation. The orange wine was distilled in a copper alembic, and the head, heart and tail fractions were collected. The orange spirit produced (heart fraction) had high concentrations of acetaldehyde, ethyl acetate, isoamyl alcohol and 2‐phenylethanol. The results showed that orange juice could be a good substrate for fermentation and distillation, and the sensory analysis performed revealed that the produced beverage had good acceptance by the tasters. Copyright © 2013 The Institute of Brewing & Distilling     

Microwave heating of apple mash to improve juice yield and quality

The effects of four heat treatments of apple mash on juice yield and quality were evaluated and compared to juice produced from unheated apple mash at 21°C. Fuji and McIntosh apple mashes were heated to bulk temperatures of 40°C, 50°C, 60°C and 70°C in a 2450 MHz microwave oven at 1500 W. Juice yield increased when mash was heated before pressing. Cider produced from the heated mashes had comparable pH, titratable acidity, and sensory characteristics to cider produced from room temperature mashes; however, total phenolic and flavonoid content of the juice increased with increasing mash temperature. Soluble solids and turbidity also increased as treatment temperature increased.     

Yield and quality of juice from passion fruit (Passiflora edulis), maypops (P incarnata) and tetraploid passion fruit hybrids (P edulis × P incarnata)

Yield and properties of juice from purple and yellow passion fruit (Passiflora edulis), maypops (P incarnata) and tetraploid hybrids of P edulis and P incarnata were compared. Weight, proportion filled, number of seeds and yield of juice per fruit were lower in tetraploid hybrids than in P edulis. Acidity and soluble solids were highest in tetraploid hybrids and lowest in maypops. Fructose, glucose, sucrose, citric and malic acids were present in all samples. Fructose and glucose were the major sugars in passion fruit; sucrose was highest in tetraploid hybrids and maypops. Citric, the predominant acid in all samples, was highest in the yellow passion fruit followed by tetraploid hybrids and purple passion fruit. Malic acid was highest in purple-flowered maypop and lowest in white-flowered maypop.     

Enzymic debittering of Indian grapefruit (Citrus paradisi) juice

The present work explores the use of enzymes for debittering grapefruit (Citrus paradisi) juice. The debittering process was optimised using a statistical approach. A full factorial design using enzyme concentration (0.25, 0.5 and 1.0 g l^?1), incubation temperature (25, 30 and 40 °C) and time of incubation (1, 2 and 4 h) as variables gave a regression equation that could predict the extent of debittering. The optimum set of conditions recommended is an enzyme concentration of 1 g l^?1 at 40 °C for 4 h. The extent of naringin breakdown achieved under these conditions was 75%. © 2002 Society of Chemical Industry     

米团花色素在果汁、果冻中的应用

考察米团花色素在果汁和果冻中的应用效果,探讨该色素的应用范围。将米团花色素添加到果汁和果冻中,以柠檬黄为对照,研究其对食品感官的影响及其在储藏过程中的稳定性。结果表明:果汁和果冻添加米团花色素后色泽良好,储藏7周后,果汁和果冻中米团花色素含量分别降低4.1%和0.6%;米团花色素可用作果汁和果冻着色剂。     

浅议从源头上把好果汁产品安全关

我国果汁产品在国际贸易中占70％多的份额,从众多消费者的饮食安全考虑,从维护国家和企业的信誉与利益出发,建议果汁产品生产企业从源头上把好产品安全关。面对来自果汁产品安全方面的压力和挑战,要从提高全民产品安全意识着手,贯彻落实和建立健全食品安全法规,利用法律、法规约束从业人员;推广GAP种植,发展无公害原料．向消费者提供安全的果汁产品。     

Multivariate data analysis applied to spectroscopy: Potential application to juice and fruit quality

The goal of building a multivariate calibration model is to predict a chemical or physical property from a set of predictor variables, for example the analysis of sugar concentration in fruits using near infrared (NIR) spectroscopy. Effective multivariate calibration models combined with a rapid analytical method should be able to replace laborious and costly reference methods. The quality of a calibration model primarily depends on its predictive ability. In order to build, interpret and apply NIR calibrations not only the quality of spectral data but also other properties such as effect of reference method, sample selection and interpretation of the model coefficients are also important. The objective of this short review is to highlight the different steps, methods and issues to consider when calibrations based on NIR spectra are developed for the measurement of chemical parameters in both fruits and fruit juices. The same principles described in this paper can be applied to other rapid methods like electronic noses, electronic tongues, and fluorescence spectroscopy.     

Simultaneous Purification of Limonin,Nomilin and Isoobacunoic Acid from Pomelo Fruit (Citrus grandis) Segment Membrane

A method was established for purification of limonin, nomilin, and isoobacunoic acid simultaneously from segment membranes of pomelo (Citrus Grandis). This method includes 3 steps, removing most impurities by macroporous resin HZ‐816, isolating limonin by High Speed Counter Current Chromatography (HSCCC), and isolating nomilin and isoobacunoic acid by semi‐preparative HPLC. Naringin was partially purified as a by‐product of this process using Sephadex LH‐20. All limonoids purified through this method reached 95% purity. The purified limonin, nomilin and isoobacunoic acid were identified according to the retention time of the standard substances using HPLC and characteristic fragment ions of LC‐MS/MS.     

Volatile flavour components of grapefruit juice (Citrus paradisi Macfadyen)

The qualitative analysis of volatile flavour components in grapefruit juice (Citrus paradisi Macfadyen) was performed using a gas chromatography/mass spectro-metry/computer system which allowed the identification of 58 components, 25 of them being reported for the first time. The aroma concentrates were obtained by an efficient simultaneous steam distillation/solvent extraction method which made it possible to identify many trace aroma components. Only quantitative differences were found in the aroma composition of fresh grapefruit juice extracted from different fruit batches of the same geographic origin during one season.     

An efficient method for the large scale isolation of naringin from pomelo (Citrus grandis) peel

An efficient and simple method was developed to isolate high-purity naringin, a bitter flavoured (to humans) flavanone glycoside with various pharmacological activities, from pomelo ( Citrus grandis Osbeck) peel in high yield. The process, which involves a simple methanol extraction followed by crystallisation in water with the addition of 14–15% (v/v) dichloromethane, gave four times higher yield compared to the same method with no dichloromethane addition and five times higher yield compared to the conventional direct hot water extraction. Through this process, albedo peels from four pomelo cultivars, Khao Taeng-gwa, Khao Yai, Khao Nam Pheung and Tong Dee, gave 24, 22, 20 and 16 mg of naringin g⁻¹ of peel dry weight, respectively. High Performance Liquid Chromatography and Nuclear Magnetic Resonance analysis of the obtained naringin indicated >98% purity. Large scale isolation was also demonstrated.     

微波辐射对柚皮抗氧化物质的浸取作用

研究了微波辐射对柚皮抗氧化物质浸取的作用及有机溶剂浸取条件的优化。微波辐射预处理试验表明 ,微波辐射的最适操作条件为 :微波辐射功率 52 5W ,辐射时间 7min。通过正交试验确定了微波辐射预处理后柚皮抗氧化物质浸取的最适条件 ,即乙醇体积分数为 70 % ,料液比为1 g∶3mL ;浸取温度为 50℃ ,振荡浸取时间为 4h。结果表明 ,微波辐射预处理有助于柚皮中抗氧化物质的浸取 ,浸取率可提高 1 2 5 %。在此条件下 ,微波辐射不影响柚皮抗氧化物质的活性 ,柚皮抗氧化物质的一次浸取率可达 60 7%。     

不同渗透条件对琯溪蜜柚品质的影响

以琯溪蜜柚为原料,采用正交实验设计,研究不同渗透液含糖量(55%、60%、65%),不同渗透温度(50、55、60℃),不同料液比(1∶6、1∶8、1∶10)对蜜柚品质的影响。测定的指标包括失水率、抗坏血酸保存率、还原糖保存率、蔗糖增加率和总酸保存率。由多指标综合评分法得出的结果表明:渗透液含糖量65%,渗透温度60℃,料液比1∶10为最佳渗透脱水条件。不同渗透条件对蜜柚各营养指标均有影响,且呈现不同的影响效果。