Selective adsorption of limonin and naringin from orange juice to natural and synthetic adsorbents

In the majority of citrus juices, bitterness is mainly ascribed to the presence of limonoids (triterpenes) and flavanone glycosides (flavonoids), namely limonin and naringin. In this study, the selective removal of limonin and naringin from citrus juice by batch adsorption to different materials was investigated. Since the removal of reducing sugars, pigments and vitamin C may also occur, the eventual adsorption of these compounds was also investigated. The following adsorbents were tested: activated diatomaceous earths, granulated activated carbon and synthetic neutral resins (Amberlite XAD-4, XAD-7 and XAD-16). Both Freundlich and Langmuir isotherm models showed a good fit to the adsorption of limonin to the resins used. Concerning naringin adsorption, a good fit of these models was only observed when the XAD-7 resin was used. Sigmoidal profiles were obtained for the adsorption of limonin to granular activated carbon. Unfavourable isotherms were also observed for limonin and naringin adsorption to activated earths. These isotherm adsorption profiles can be explained by a multilayer adsorption phenomenon. The highest adsorption efficiency for the bitter compounds was observed when synthetic neutral resin, Amberlite XAD-7 was used. The separation factor limonin/naringin varied from 16 (with earths) to 57 (with XAD-7 resin). The adsorption of sugars and pigments to the resins was low. No adsorption of vitamin C was detected for any of the adsorbents tested. The estimated affinity and separation factors show that the neutral resins tested are adequate for the selective removal of limonin from orange juices. The estimated values of free energy of adsorption, lower than -13.3 kJ mol^-1 K^-1, indicate that a physiosorption process occurred.     

The use of different adsorbents for selective removal of compounds from olive residue oil miscella

The selective removal of several impurities from a solution of crude olive residue oil in n-hexane (miscella) using batch adsorption by different materials, used separately or in sequence, was investigated. The following adsorbents were tested: activated diatomaceous earths, powdered activated carbon and synthetic neutral resins ("Amberlite XAD-4, XAD-7, XAD-16). The adsorption efficiency of every group of compounds depended on the adsorbent and the ratio (amount of adsorbent/amount of oil) used. The activated earths and carbon were very much more effective in the adsorption of the compounds from the miscella than the resins. Results were similar for every resin tested. An effective removal of green pigments (chlorophylls and pheophytins) and carotenoids was achieved with every adsorbent tested. With respect to the adsorption of conjugated hydroperoxides (HP), a removal of 50-60% was attained with activated carbon and earths, in contrast to a 20% removal by the resins. For the final oxidation products (FOP), a 60% removal was observed with powdered carbon, 20-30% with earths and 20% with resins. A removal of 20% of free fatty acids (FFA) by activated earths or powdered carbon and 40% by the resins was observed. When the adsorbents were used in sequence (carbon or earths followed by XAD-7 resin), the resin was able to adsorb the remaining FFA, HP and FOP.     

不同柑橘品种全果制汁适宜性分析

为了研究不同品种柑橘全果制汁的品质特性,对全国7 个地区30 个不同品种柑橘（包括蜜橘、椪柑、冰糖橙、脐橙等）的理化、营养、加工等18 项指标进行测定,并采用主成分分析法筛选出适宜全果制汁的品种。结果表明：不同品种的柑橘全果中籽数和总黄酮、柠檬苦素、诺米林含量差异较大,而出汁率、色度等指标差异较小。经主成分分析提取出6 个特征值大于1的因子,前6 个主成分分别对应柑橘全果苦味因子、加工因子、颜色因子、营养因子、酸度因子和甜度因子,其累积方差贡献率为82.566%。从6 个因子综合考虑,发现‘纽荷尔脐橙-II’、‘福本脐橙-I’、‘福本脐橙-II’、‘冰糖甜橙’、‘道州脐橙’、‘崀丰7904脐橙’为较适宜全果制汁的品种。本研究结果为选择适用于全果制汁的柑橘品种提供了参考依据。     

不同酵母对脐橙果酒品质的影响

为了筛选适宜脐橙果酒加工的优良酵母,本文以崀丰脐橙为原料,选取BV818、DV10、RV002、RV171、K1和L2323共6种酵母进行发酵,通过超高效液相色谱和顶空固相微萃取-气相色谱质谱联用仪分析理化指标和挥发性香气物质,采用气味活度值及主成分分析法进行分析及综合评价。结果表明:RV002的发酵速率最快,K1、L2323、DV10和RV002发酵后脐橙酒总黄酮含量高于CK,RV171、RV002、DV10与K1中柠檬苦素类物质"后苦味"降低较明显。6个酒样共检测出86种香气成分,每种酒样香气成分数为24~39种,醇类物质含量最高,分别占香气总量的49.44%~78.58%,酯类物质OAV>1的种类最多,对酒的香气贡献最大。异戊醇、辛酸乙酯、乙酸苯乙酯、癸酸乙酯等是脐橙果酒的主体香气物质,使果酒花香、果香特征突出。通过主成分分析提取5个主成分,累计方差贡献率为93.99%,能较好体现脐橙果酒的综合品质,排名从高到低依次为DV10、RV171、RV002、L2323、BV818、K1,结合感官评价,DV10为适宜脐橙果酒酿造的酵母。     

Reduction of bitterness and acidity in grapefruit juice by adsorptive processes

By choosing an appropriate adsorbent, the bitter principles (naringin and limonin) and titratable acids could be removed from grapefruit juice in varying combinations. For example, Amberlite XAD-7 removed about 63% naringin, 85% limonin and 3% titratable acids and Deacidite-FFIP removed about 20% naringin, 8% limonin and 23% titratable acids when contacted for 1 h with grapefruit juice at the rate of 20 g (dry wt) of adsorbent per litre of juice. Such treatments, applied consecutively, would eliminate excessive bitterness and acidity from juices containing up to 2 g naringin and 36 mg limonin litre^?1 and with a total soluble solids:titratable acid ratio of < 6. The adsorbents are readily available, may be used as supplied and can be reactivated simply and economically; some of them have already been approved for use with foods, and such approval seems possible for the others.     

Limonin Monolactone, the Nonbitter Precursor Responsible for Delayed Bitterness in Certain Citrus Juices

SUMMARY– Tissues of early-season navel oranges and grapefruit were found by paper electrophoretic procedures to contain a nonbitter precursor of limonin, but no significant amounts of limonin. Limonin is the intensely bitter triterpenoid dilactone responsible for the bitterness which develops in certain navel orange juices on standing. The nonbitter precursor was identified as limonin monolactone by comparison with the authentic compound prepared by partial hydrolysis of limonin and by acid-catalyzed conversion into limonin. Limonin monolactone is stable in the tissues of the intact fruit (which are not bitter) because it is apparently not in direct contact with the acidic juice. It is slowly converted into limonin (and the juice becomes bitter) when the fruit tissues come in contact with the juice, after the juice is expressed from the fruit. Limonin monolactone was not detected in late-season navel oranges or grapefruit. This agrees with the fact that juice made from these fruits does not contain limonin. Work is in progress to determine whether the naturally occurring limonin monolactone is the A-ring monolactone, the D-ring monolactone, or a mixture of the two.     

Effect of cellulose acetate gel bead column treatment on the acceptability and composition of navel orange juice

Reducing the limonin contents of pasteurised Navel orange juices by passage through a cellulose acetate gel bead column at ambient temperature significantly decreased the bitterness and increased the flavour and acceptability of the juices as measured by taste panel scores. Debittering by adsorption of limonin on to the cellulose acetate gel bed was less effective when applied to fresh unpasteurised juice and to chilled, pasteurised juice. The cellulose acetate gel column was shown to be selective for limonin, in one run removing 55% of the initial limonin content; a small quantity (12%) of flavonoids and minor amounts (< 5%) of ascorbic acid, orange oil and titratable acid were also removed but the treatment had no effect on amino acid nitrogen.     

An optimal extraction solvent and purification adsorbent to produce anthocyanins from black rice (Oryza sativa cv. Heugjinjubyeo)

Black rice was used to produce anthocyanins, an important natural red food colorant. Integrated methods for extraction and purification of anthocyanins were investigated. Four solvents and 6 adsorbents were used for extraction and purification, respectively. Acidified 70%(v/v) ethanol resulted in the highest anthocyanin extract concentration of 461.72 mg/L. Amberlite XAD7HP had the highest adsorption capacity of 0.406±0.010 mg/g of adsorbent and desorption capacity of 0.252±0.016 mg/g of adsorbent. Acidified ethanol effectively eluted anthocyanin pigments from Amberlite XAD7HP at a concentration of 60%(v/v). Experimental adsorption data best fit to pseudosecond-order kinetic and Langmuir isotherm models. Purification parameters were optimized through dynamic adsorption/desorption experiments with Amberlite XAD7HP. The concentration of sugars (impurities) decreased from an initial 452.78 μg/mL to 169.75 μg/mL after purification.     

大孔吸附树脂对石榴皮多酚的分离纯化

石榴皮中多酚含量丰富,具有抗氧化、抗衰老、抗癌防癌、抗菌、润肤美容、降血压和预防心脑血管疾病等多种生理和药理活性。在食品、医药和日用化学品等领域显示出巨大的应用价值。从XAD-16、XAD-1180、XAD-7HP、D101、DM-11、DM130、SP-700、SP-850、X-5、AB-8和H-103大孔吸附树脂中通过静态实验筛选出SP-700树脂,详细研究了其对石榴皮总单宁的静态与动态吸附和解吸性能。结果表明,SP-700树脂对石榴皮多酚的饱和吸附量为70.52mg/g(干树脂),吸附等温线符合Freundlich方程,为多分子层吸附,饱和吸附时间为5h,适宜解吸剂为体积分数70%的乙醇溶液,测定20、25、30、35℃下吸附等温线,表明最适宜的吸附温度是25℃,此时最大吸附量达到96.71mg/g(干树脂);以5mg/mL质量浓度的石榴皮提取液上柱,流速为4～4.5BV/h时,树脂的多酚穿透吸附容量65.72mg/g(干树脂),3.5BV体积分数70%的乙醇溶液可将吸附于柱上的石榴皮多酚完全洗脱。以该条件纯化石榴皮多酚提取物时,纯化样的收率为26.5g/100g(干石榴皮),多酚质量分数从48%提高到...     

大孔树脂提取侧孢短芽孢杆菌抗菌肽brevilaterin

为开发brevilaterin的高效提取技术,首先,通过考察大孔树脂对brevilaterin的吸附解吸附能力,筛选出吸附解吸附效果好的大孔树脂XAD-7HP,并通过优化获得最佳工艺条件,即将大孔树脂XAD-7HP以30 g/L的添加量于35℃条件下吸附发酵液中的brevilaterin,吸附时间为1.5 h,再采用70%乙醇解吸附2 h,brevilaterin回收率达到82%。通过吸附等温线模型及吸附动力学研究了XAD-7HP对brevilaterin的吸附机理,发现XAD-7HP对brevilaterin的吸附符合Langmuir模型与拟二级动力学,说明XAD-7HP吸附brevilaterin的过程属于单分子层的化学吸附;Elovich方程拟合结果显示,吸附过程主要分为3个阶段:边界层扩散、颗粒内扩散、最终平衡。大孔树脂法提取brevilaterin工艺绿色环保、操作简单、成本低廉,为brevilaterin的工业化生产提供了技术支持。     

一种新型复合果蔬醋饮料的研制

研究复合果蔬醋饮料的发酵、制作工艺、配方以及稳定性.以新鲜甜橙为原料,取汁,进行酒精发酵和醋酸发酵,制得甜橙醋酸液;以新鲜胡萝卜、番茄、山楂为原料,分别制取蔬菜汁.将甜橙醋酸液和蔬菜汁进行合理混合,通过对物料配比的研究以及糖酸比等的调整,确定最佳混合果蔬醋饮料的配方,并对饮料的色泽稳定性进行实验研究.最终制得一种口感、营养、外观俱佳的复合果蔬醋饮料.     

Effect of refrigerated storage on vitamin C and antioxidant activity of orange juice processed by high-pressure or pulsed electric fields with regard to low pasteurization

A better knowledge of the effect of refrigerated storage on the nutritional and antioxidant characteristics of foods processed by emerging technologies with regard to thermal traditional technology is necessary. Thus, freshly squeezed orange juice was processed by high-pressure (HP) (400 MPa/40 °C/1 min), pulsed electric fields (PEF) (35 kV/cm/750 μs) and low pasteurization (LPT) (70 °C/30 s). The stability of vitamin C and antioxidant activity was studied just after treatment and during 40 days of refrigerated storage at 4 °C. The determination of total vitamin C (ascorbic acid plus dehydroascorbic acid) was achieved by HPLC whereas the antioxidant activity was assessed by the measurement of the DPPH• radical scavenging. Just after treatment, all treated orange juices showed a decrease lower than 8% in vitamin C content compared with the untreated one. At the end of refrigerated storage, HP and LPT juices showed similar vitamin C losses (14 and 18%, respectively) in relation to untreated juice, although HP juices maintained better the vitamin C content during more days than LPT juices. Regarding antioxidant activity, after 40 days at 4 °C, differences among treated juices were no significant in terms of antiradical efficiency (AE=1/EC₅₀T_EC50). HP and PEF may be technologies as effective as LPT to retain antioxidant characteristics of orange juice during refrigerated storage.     

Suitability of solid phase extraction and flame atomic absorption spectrometry for manganese partitioning in red wines

A suitability of a tandem column assemblage comprising a non-ionic adsorbing resin Amberlite XAD-16 and a strong cation exchange resin Dowex 50W-x8-200 linked in a series for the fractionation of Mn in wine was evaluated. Sorption and desorption properties of both sorbents towards simple ions of Mn(II) and its complex ions with citric and tannic acids were preliminary examined. The partitioning of Mn in wine was investigated using a solid phase extraction procedure developed and it resulted in classification of phenolic bound, cationic and residual fractions of Mn. It was found that in red bottled wines analysed Mn is predominantly present in the forms of cationic species, likely to be simple ions and complex ions with low molecular weight hydroxy acids. This fraction of a mean donation of 80% was assumed to be the most bioavailable.     

6 种水果中键合态香气成分的气相色谱-质谱法鉴定与比较

以菠萝、草莓、苹果、梨、香橙和红提6 种水果为研究对象,通过Amberlite XAD-2树脂吸附、乙醇洗脱的方法,分离得到其对应的键合态香气成分,酶解后所释放的香气成分经气相色谱-质谱检测分析,得到各水果中键合态香气成分的种类和含量。结果表明,各种水果所鉴定出的键合态香气物质种类分别为：苹果18 种、梨33 种、草莓32 种、香橙13 种、菠萝15 种、红提16 种。其中,醇、酚类物质含量总体相对较高,草莓中键合态香气物质的总含量最为丰富,达34.29 mg/L。苯甲醇、苯乙醇、丁香酚等香气成分在至少3 种水果中被检出。各种水果中含量较高的键合态香气种类有所不同。部分水果中的键合态香气物质在文献中鲜见报道。     

大孔吸附树脂吸附分离高活性玉米抗氧化肽

采用大孔吸附树脂对玉米抗氧化肽进行分离,通过单因素试验得出XAD-7HP树脂为最适树脂,在此基础上,研究不同pH值条件下的静态吸附能力和不同解吸剂的静态解吸能力等实验,确定玉米抗氧化肽吸附分离的基本参数为pH7.0、解吸剂体积分数70%。通过动态吸附分离实验得出,该树脂可以达到分离纯化玉米抗氧化肽的目的,而且分离后的玉米肽的抗氧化活性比原液提高了1倍。     

基于组合色谱技术的蓝莓果实中花色苷元制备

首先采用液液萃取及大孔树脂层析技术研究花色苷的制备方法,萃取剂为乙酸乙脂,大孔树脂为Amberlite XAD-7HP,在此基础上制得花色苷粗提液。花色苷经酸水解、浓缩后,采用固相萃取技术（C18小柱）对花色苷元进行除酸、除糖处理,制得了纯度为70.2%的花色苷元混合物。最后采用半制备型高效液相色谱技术实现4 种主要花色苷元单体的分离,分别为飞燕草素（纯度98.2%）、矢车菊素（纯度96.3%）、牵牛花素（纯度92.6%）、锦葵色素（纯度90.5%）。本研究可为花色苷元的规模化制备及后期功能活性研究提供技术参考和依据。     

Solid-phase extraction (SPE)—a comparison of 16 materials for the purification of anthocyanins from aronia melanocarpa var Nero

There is an increasing interest in anthocyanins, not only as natural food colourants but also for pharmaceutical products due to their antioxidative potential. Common extraction procedures of anthocyanins from plant material are non-selective and yield pigment solutions with large amounts of by-products such as sugars, sugar alcohols, organic acids, amino acids and proteins. Some of these impurities may accelerate anthocyanin degradation or cause problems in further processing steps such as spray drying. In order to obtain a highly concentrated and purified anthocyanin pigment from black chokeberry (Aronia melanocarpa var Nero), juices and skin extracts were purified by solid-phase extraction (SPE). Sixteen solid-phase materials were tested on a laboratory scale, whereby the anthocyanin and sugar content of collected fractions were determined to represent elution profiles. Among these, reversed-phase silica gels and macroreticular non-ionic acrylic polymer adsorbents such as Serdolit PAD IV or Amberlite XAD-7 turned out to be most suitable. SPE was investigated with these materials in an enlarged scale, improving elution gradient and column purification. Amberlite XAD-7 was successfully applied in a 36-litre-scale separation. © 1998 Society of Chemical Industry.     

基于色谱质谱联用技术分析纽荷尔脐橙果汁及其果酒的香气成分和苦味物质

为了研究纽荷尔脐橙果汁、果酒的香气成分及其苦味物质,本文通过顶空固相微萃取技术富集其中香味物质并采用气相-质谱联用技术测定所含物质及相对含量。其中果汁中鉴定化合物31种,主要成分为D-柠檬烯(33.74%)和巴伦西亚橘烯(25.12%);果酒中鉴定化合物27种,主要成分为4-萜烯醇(13.45%)、芳樟醇(8.54%)、苯乙醇(8.45%)以及高级脂肪酸乙酯。通过QuEChERS前处理方法,PSA填料净化,采用液相-质谱联用技术测定果汁、果酒中苦味物质含量,其中果汁中主要苦味物质为橙皮苷(13.4 μg/mL)、柠檬苦素(4.43 μg/mL)、橙皮素(0.02 μg/mL)、诺米林(0.07 μg/mL),果酒中主要苦味物质为橙皮苷(16.7 μg/mL)、柠檬苦素(0.05 μg/mL)、橙皮素(0.08 μg/mL)。酿造过程中,柠檬苦素通过酵母发酵、酶的作用等原因逐渐降解,转变为没有苦味的脱氢柠檬苦素及酸类,因此果酒中柠檬苦素的含量降低至0.05 μg/mL,橙皮苷和橙皮素的含量没有显著变化。     

Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice. Part I: Impact on overall quality attributes

Mild heat pasteurization, high pressure processing (HP) and pulsed electric field (PEF) processing of freshly squeezed orange juice were comparatively evaluated examining their impact on microbial load and quality parameters immediately after processing and during two months of storage. Microbial counts for treated juices were reduced beyond detectable levels immediately after processing and up to 2 months of refrigerated storage. Quality parameters such as pH, dry matter content and brix were not significantly different when comparing juices immediately after treatment and were, for all treatments, constant during storage time. Quality parameters related to pectinmethylesterase (PME) inactivation, like cloud stability and viscosity, were dependent on the specific treatments that were applied. Mild heat pasteurization was found to result in the most stable orange juice. Results for HP are nearly comparable to PEF except on cloud degradation, where a lower degradation rate was found for HP. For PEF, residual enzyme activity was clearly responsible for changes in viscosity and cloud stability during storage.

Industrial relevance

Development of mild processing technologies with a minimal impact on fruit juice can be considered as a true alternative of fresh fruit. The present work presents a fair comparison of mild heat treated, high pressure (HP) and pulsed electric field (PEF) processed orange juice as an alternative for thermal pasteurization. Orange juices were monitored during two months of storage.