Effect of harvesting time and fruit size on titratable acidity, soluble solid and distribution of limonin in Thai tangerine juice

The effect of fruit size and harvesting of Thai tangerine fruit ( Citrus reticulata , Blanco) at different growth stages, 8–12 months after fruit set, on the distribution of limonin in whole fruit as well as in the individual fruit parts and extracted juice was investigated. The highest limonin concentration was observed in seed, followed by albedo, flavedo, segment membrane and juice sacs in decreasing order. The limonin concentration in juice as well as in whole fruit was decreased when fruit was harvested 8–12 months of fruit set. Increasing harvesting time from 8 to 12 months showed corresponding decreases in the amount of limonin in flavedo, albedo and seed. There was a decrease in titrable acidity and increase in total soluble solid and total soluble solid/titrable acidity ratio of juice with a later than normal harvesting time. However, fruit size showed no effect on limonin content and other properties of juice extracted from tangerine.     

砂糖橘精油化学组成及对指状青霉的抑菌活

采用水蒸气蒸馏法提取砂糖橘(Citrus reticulate Blanco)果皮精油,并用GC-MS对其成分进行分析,共鉴定出17种成分,主要包括柠檬烯(77.99%)、β-月桂烯(3.74%)、β-水芹烯(2.78%)、罗勒烯(2.64%)、β-芳樟醇(2.35%)、α-蒎烯(1.60%)、正辛醇(1.54%)、癸醛(1.24%)、4-松油醇(1.10%)和4-十一烯(1.04%)等。测定不同添加量(0.16、0.31、0.63、1.25、2.50、5.00、10.00μL/mL)砂糖橘精油对指状青霉孢子萌发和菌丝体生长的作用。结果表明：低添加量(＜2.5μL/mL)砂糖橘精油对指状青霉孢子萌发无影响甚至有促进作用,对指状青霉菌丝体生长有轻微的抑制;而高添加量(10μL/mL)则显著抑制孢子萌发和菌丝体生长(P＜0.05)。本实验表明砂糖橘精油在防治指状青霉具有一定作用。     

Biosynthesis of flavour compounds in Muscat Gordo Blanco grape berries

Inflorescences of the floral grapevine cv Muscat Gordo Blanco (syn. Muscat of Alexandria) were grown on their own shoots until maturity or, after approach-grafting before flowering, on the shoots of the non-floral cv Shiraz (in the glasshouse) or Sultana (in the field). The flavour compounds of their berries were compared with those in the berries of the non-floral cultivars, grown either on their own shoots or, by grafting, on the shoots of the Muscat cultivar. For this, monoterpene glycosides were isolated from the fruits, enzymatically hydrolysed and the released monoterpene aglycons were liquid-liquid extracted and analysed by GC-MS. The Muscat Gordo Blanco berries of ungrafted bunches and of bunches grafted onto Shiraz or Sultana vines yielded fruit with monoterpenes at levels and types typical of this floral grape variety. The berries of Shiraz and Sultana bunches contained only low levels of monoterpene glycosides both on their own shoots or grafted onto Muscat shoots. The lack of difference between flavour compounds in grafted and non-grafted fruit indicate that aroma compounds are synthesised in the berries and that their presence is determined by the genotype of the grape bunch rather than by the genotype of the vine.     

Amounts of glycosides in grapevine organs during berry development

Whole berries, leaf blades and petioles from Muscat Gordo Blanco (syn. Muscat of Alexandria), Sultana and Flame Seedless vines were sampled at intervals from three weeks after flowering to fruit ripeness. The glycosidically-bound constituents present in the samples were quantified through a determination of the glycosyl glucose. At the stage of berry ripeness, the concentration of glycosides per gram fresh weight in the leaf blades was 10–30 times higher than in the fruit. During berry development glycoside concentrations increased in leaf blades and petioles but decreased in fruit. However, when expressed on a per berry basis, the levels of glycosides in the fruit increased as ripening progressed; the levels in ripe fruit were high in Muscat Gordo Blanco and low in Sultana. Further experimentation will be needed to establish whether the glycosides are synthesised in the leaves and transported to the berries or synthesised independently in both organs.     

Fearscapes: Caracas Postcards from a Violent City

Venezuelan architect, artist and educator Eduardo Kairuz reveals how beneath the stereotypical view of Caracas as the ‘Murder Capital of the World’ lies a history of savage imposition, dating back to its founding in the 16th century and its colonial past and manifested today in the stark social segregation between parts of the city. Copyright © 2010 John Wiley & Sons, Ltd.     

CrWSKP1, an SKP1-like Gene,Is Involved in the Self-Incompatibility Reaction of “Wuzishatangju” (Citrus reticulata Blanco)

Plant S-phase kinase-associated protein 1 (SKP1) genes play crucial roles in plant development and differentiation. However, the role of SKP1 in citrus is unclear. Herein, we described a novel SKP1-like gene, designated as CrWSKP1, from “Wuzishatangju” (Citrus reticulata Blanco). The cDNA sequence of CrWSKP1 is 779 base pairs (bp) and contains an open reading frame (ORF) of 477 bp. The genomic sequence of the CrWSKP1 gene is 1296 bp with two exons and one intron. CrWSKP1 has high identity with SKP1-like genes from other plant species within two conserved regions. Approximately 85% of pollen tubes of self-pollinated CrWSKP1 transgenic tobaccos became twisted at four days after self-pollination. Pollen tube numbers of self-pollinated CrWSKP1 transformants entering into ovules were significantly fewer than that of the control. Seed number of self-pollinated CrWSKP1 transformants was significantly reduced. These results suggested that the CrWSKP1 is involved in the self-incompatibility (SI) reaction of “Wuzishatangju”.     

Effect of maturity and processing on bitter compounds in Thai tangerine juice

Optimum conditions of fruit maturity and processing for improved quality of Thai tangerine fruit juice were evaluated. Limonin and naringin components causing bitterness, acidity, total soluble solids and vitamin C were quantified in specified fruit setting and processing conditions.
Higher limonin contents were observed in tangerine fruits harvested early in the season of 1989, whereas naringin contents gradually decreased with maturity. The optimum harvesting time for Thai tangerine fruit which meets the worldwide quality indicators of extracted juice was nine months after fruit set.
Low temperature storage of tangerine juice was only effective in delaying limonin formation if not pasteurized, which resulted in higher limonin concentrations at the start of the storage period. However, naringin concentrations of tangerine juice were not affected by storage conditions and the pasteurization process. Lower extraction pressure of juice resulted in low limonin and naringin concentrations.     

Occurrence of anthocyanin pigments in berries of the white cultivar Muscat Gordo Blanco (Vitis vinifera L.)

Rose coloration of skin was observed to sometimes develop late during ripening on the normally white grape berries of cv. Muscat Gordo Blanco. The nature of the pigment was investigated by HPLC analysis of skin extracts of single berries. The predominant anthocyanin was identified as cyanidin-3-glucoside with minor amounts of delphinidin- and peonidin-3-glucosides. This composition resembles the skin composition of coloured, small-seeded muscat cultivars which it also resembles by the monoterpene composition of the juice. The pigments occurred only in berries with levels of total soluble solids in excess of 24°Brix in the juice and such berries tended to have smaller fresh weight. Berry pigmentation occurred on vines with various root systems. The specific conditions under which pigment developed in Muscat Gordo berries may offer a useful tool in the study of anthocyanin biosynthesis.     

Application of 13C nmr spectroscopy to the elucidation of the electrochemical oxidation mechanism of the l-ascorbic and d-araboascorbic acids

The previously proposed electrochemical oxidation mechanism of the l-ascorbic and d-araboascorbic acids in basic medium must be rejected because of the variation in the carbon chemical shifts and coupling constants with the pH, which shows that the supposed rupture of the furanose rings at pH ～ 9 does not occur. Electrolysis in basic medium yields the same products as those obtained when the pH of the products of the electrolysis in acid medium are raised to pH ～ 11. This suggests that the oxidation mechanisms in acid and basic media are similar. The assigned carbon chemical shifts of the oxidation products in acid medium $\text{3}$ (or $\text{4}$) and in basic medium $\text{5}$ (or $\text{6}$) and $\text{7}$ (or $\text{8}$) are reported.     

AB-8大孔吸附树脂精制芦柑皮总黄酮及黄酮类化合物的分离

目的：研究AB-8大孔吸附树脂精制芦柑皮总黄酮的工艺条件及芦柑皮黄酮类化合物的分离纯化。方法：采用AB-8大孔吸附树脂动态法精制芦柑皮总黄酮,考察上样液总黄酮质量浓度、pH值、上样流速、洗脱液乙醇体积分数对吸附解吸性能的影响;然后将精制的芦柑皮总黄酮经硅胶柱层析、半制备高效液相等技术进行分离纯化,并根据理化性质和波谱数据鉴定化学结构。结果：AB-8大孔树脂精制芦柑皮总黄酮的最佳工艺条件为上样液总黄酮质量浓度3.03 mg/mL、上样液pH 3.0、上样流速3.0 BV/h、洗脱液乙醇体积分数为90%,最优条件下可使芦柑皮总黄酮的纯度从17.8%提高到63.1%;此外,从精制的芦柑皮黄酮中分离到8 个黄酮类化合物,分别鉴定为：橘皮素、川陈皮素、4’,5,7,8-四甲氧基黄酮、5-去甲基-橘皮素、橙黄酮、橙浸膏、柚皮苷、橙皮苷。结论：AB-8大孔树脂能很好地富集纯化芦柑皮总黄酮,该法简单、可行;从精制的芦柑皮黄酮中分离到8 个黄酮类化合物,其中,4’,5,7,8-四甲氧基黄酮、5-去甲基-橘皮素、橙浸膏、柚皮苷、橙皮苷首次从芦柑皮中分得。