Effect of Membrane Material on the Separation of Proteins and Polyphenol Oxidase in Ultrafiltration of Potato Fruit Juice

Ultrafiltration was applied to diluted potato fruit juice, a side-stream from potato starch production. The aim of the study was to selectively concentrate the potato proteins in the permeate, while isolating polyphenol oxidase (PPO) in the retentate. A profound difference was found in protein retention between two 300-kDa molecular weight cutoff (MWCO) ultrafiltration membranes, of either regenerated cellulose (RC) or polyethersulfone (PES). The use of the 300-kDa MWCO RC membrane resulted in a twofold higher retentate protein content as well as total retention of all PPO activity, as compared with the PES membrane. Comparison tests with 100- and 300-kDa MWCO PES membranes indicated that concentration polarization and gel layer formation, and not MWCO definitions, were governing factors for protein retention, since proteins with a MW of 10 kDa were retained in all the experiments. PPO activity in potato fruit juice was measured in permeate and retentate to assess its selective retention by the applied ultrafiltration processes. Of the specific PPO activity, 94–100 % was retained by either 300 MWCO RC or 100 MWCO PES, while only 49 % specific activity was retained by the 300 MWCO PES. By in situ blotting experiments, the molecular weight of active PPO was found to be present at three different molecular weights, at positions of 40, 47, and 100 kDa, respectively, with the major activity present at 47 kDa.     

桂圆肉-红枣复合饮料的研制

以桂圆肉、红枣为原料,制成桂圆肉-红枣复合饮料.用正交试验方法,得出最佳配方.对影响复合饮料稳定性的稳定剂进行了探讨,结果表明,添加0.10% CMC-Na+0.08%明胶构成的复合稳定剂稳定效果较理想.并介绍了该复合饮料的生产工艺、工艺要点和配方.     

果蔬汁新型包装研究进展

随着人们对食品营养和安全的关注和要求,\     

A New System for the Production of Starch and Protein from Potato

This article describes a technical system for the manufacture of starch, protein and fiber concentrates from potatoes without addition of process water. Because of a gentle drying, the excellent physical characteristics of the potato protein are maintained and make it applicable in foods. Chemical composition of the starch and protein has been examined. There seems to be good possibilities for application of the products. Calculations indicate a favorable economy using existing spray drying plants, which are idle in the potato season. Spray drying results in an increased energy consumption but this seems to be balanced by a larger product yield/t potatoes, the saving of waste water installations and the excellent physical and nutritional properties of the protein.     

基于原料与果汁品质的蓝莓果实加工性能评价

以‘蓝金’、‘瑞卡’、‘N5’等12个辽南露地栽培蓝莓品种果实为试材,通过果实外观、营养品质及加工性能指标的观测与分析,筛选加工适宜品种。结果表明,蓝莓果实以蓝色为主,呈不同程度扁球形,表面附着果粉,单果重0.95~2.63 g;含水量>80%,果越大,含水量越高,果型越扁,果实中均含有果糖、葡萄糖、草酸、奎尼酸、苹果酸、莽草酸和柠檬酸,果糖与葡萄糖含量相当,柠檬酸含量显著高于其它有机酸（P<0.05）,属于已糖积累型、柠檬酸优势型果品。供试品种果实中均含有钾、镁、钙、铁、锰、锌和铜元素,含量依次递减,钾含量最高（5786 mg?kg?1）,极显著高于其它元素（P<0.01）,‘达柔’果实中钾含量（7400 mg?kg?1）最高。不同品种果实不添加果胶酶处理出汁率差异极大（变异系数达60.42%）,添加果胶酶处理出汁率差异很小（变异系数仅3.88%）,添加果胶酶处理出汁率及果汁可溶性糖、可滴定酸含量明显提升,添加果胶酶处理能够提高果汁产率和质量。果实中果糖和葡萄糖含量越高,果汁中可溶性糖含量越高（相关系数为0.96和0.98）;果实中柠檬酸和奎尼酸含量越高,果汁中可滴定酸含量越高（相关系数为0.81和0.71）。‘日出’、‘蓝金’和‘北卫’3个品种可溶性糖（>90 mg?g?1）、有机酸含量（>10 mg?g?1）和出汁率（>74.6%）均较高,是较好的加工品种。综上,‘日出’、‘蓝金’和‘北卫’3个品种果实营养丰富、出汁率高,是加工的理想原料。     

果蜜啤酒的研制

采用蜂蜜和果汁为辅料生产的果蜜啤酒风味独特、营养价值高。其为蜂蜜的深加工，创造更高的附加值产品提供了出路。     

Comparative Analysis of the Antioxidant Capacity of Selected Fruit Juices and Nectars: Chokeberry Juice as a Rich Source of Polyphenols

The bioactive compounds, and hence the antioxidant capacity, of fruit juice are affected by a given type of juice and fruit processing conditions. In this study, some polyphenol-rich juices and nectars were compared, considering the manufacturing conditions (Stage I). Organic chokeberry juice was determined to possess the highest antioxidant capacity, which was 4- to 10-fold higher than in other popular juices. Subsequently, this juice was analyzed for selected flavonoids (flavanols, flavonols, flavones) and phenolic acids (Stage II). The results showed that chokeberry juice was a rich source of chlorogenic and neochlorogenic acids. The high total content of polyphenols and high antioxidant capacity encourage further clinical research on chokeberry juice, in the context of cardiovascular diseases prophylaxis.     

An Aqueous High-Performance Liquid Chromatographic Procedure for the Determination of 5-Hydroxymethylfurfural in Honey and Other Sugar-containing Materials

ABSTRACT: A new, all aqueous high-performance liquid chromatography (HPLC) procedure for the determination of 5-hydroxymethylfurfural (HMF) in honey and other sugar-containing materials was developed without harmful chemicals. The method involved dilution of the sample in water and the analysis of the diluent using an HPLC system equipped with an absorbance detector and a 30-mm sulfonated poly(styrene-divinylbenzene) cation exchange column. Water was used as the mobile phase at a high flow rate of 2.00 mL/min Using this high flow rate in conjunction with a column heater set at 55°C, HMF eluted in less than 4 min. Overall precision was less than 1% relative standard deviation, recovery of HMF from spiked samples was approximately 99%, and there were no interferences from similar compounds such as 2-furfural and 5-methylfurfural. Several sugar-containing materials were analyzed by this method where the results compared well with the classic Winkler spectrophotometric procedure, but not as well with a commonly used reverse-phase HPLC technique. In addition, several consumer products were also analyzed for their HMF content.     

A Rapid Method for Separation and Quantitation of D-Malic Acid in Fruit Juice

A HPLC method using an aqueous mobile phase containing the chiral ligand-exchanger Cu II-L-valine complex at pH 5.5 with a polystyrene divinyl-benzene copolymer column was used to resolve D-malic acid in apple, pear, and Concord grape juices. D-malic acid was detected and quantitated at 330 nm in less than 15 min per sample. The detection limit appeared to be 2 mg/100 mL D-malic acid in 12 Brix juice, or 0.33% total malic acid in a typical apple juice containing 0.6 g/100 mL using the described procedure.     

Effects of Fruit Storage and Processing on Clarity, Proteins, and Stability of Granny Smith Apple Juice

Granny Smith apples were processed into juices and concentrates from fruits which had been stored at 1°C for three months (short-term, ST) and nine months (long-term, LT). Total soluble proteins decreased with storage time of fruits. Juices processed from ST fruits were more resistant to haze formation (heat stability test) than those processed from LT fruits. For juices processed from ST apples, haze formation was related to proteins in the MW range of 21,000 to 31,000 daltons. For juices processed from LT apples, haze formation was not only related to proteins but also to other components in the juices. Fining was recommended to prevent haze and sediment formation.     

A Procedure for Gas Chromatographic Analysis of Free Amino Acids in Meats

SUMMARY— A gas liquid chromatography (GLC) procedure was developed to quantitatively measure the free amino acid content of meat and meat products. The amino acids were extracted from the meats with water and purified using dialysis and ion exchange chromatography. n-Butyl N-trifluoro-acetyl amino acid derivatives were prepared and analyzed on the gas chromatograph. Factors used for quantitative purposes were calculated using the peak areas and concentrations of known amino acid derivatives.
The isolation and purification procedures were able to remove all carbohydrates, proteins, and 98% of all inorganic salts from the amino acid solutions. Eleven of the common amino acids were completely resolved using the GLC condition described in this investigation. In addition, three GLC peaks contained two amino acids each. The procedure was able to detect free amino acid in sausage in concentrations as low as .01mg/g.     

A Novel Natural Source Sterculia foetida Fruit Shell Waste as Colorant and Ultraviolet Protection for Linen

There has been a growing interest in natural dyes and consciousness about ill effects of ultraviolet rays on the human skin. This paper discusses dye extraction from the fruit shell waste of Sterculia foetida and its application on linen fabric for dyeing as well as ultraviolet protection (UPF) property. Optimal results were achieved for dyeing at 90°C for 60 min at 30% concentration of the dye on the weight of fabric using pre- and post-mordant dyeing techniques. Dyeing on linen fabric with and without mordant showed very good results in terms of different hues of color and UPF. Treated fabrics showed substantial increase in color depth and good to very good wash, light and rubbing fastness properties for both with and without mordant-dyed linen fabrics. The results confirmed that natural dye from Sterculia foetida fruit shell extract has potential applications for linen dyeing and producing a good to very good UPF.     

不同品种橄榄汁理化性质与制汁特性的研究

通过对我国橄榄主产区福建主栽的5个橄榄品种的果汁理化性质进行测定、分析,结果表明:惠圆橄榄出汁率最高,果汁褐变度轻、色泽鲜亮、感官品质良好,适合作为澄清型果汁的加工原料;长营橄榄的果汁糖酸含量最高,色泽鲜艳,适合加工成浑浊型果汁,但是其果汁褐变速率最快,耐贮性较差,因此加工过程应注意护色;檀香橄榄汁的可溶性糖含量最高、褐变程度轻、出汁率较高,且酚糖比最低、果汁风味好,是制汁与鲜食兼用的良好品种。因此,所研究的5个品种中,惠圆、长营及檀香橄榄具有较好的制汁特性,而自来圆和诏安橄榄两个品种各项制汁指标均没有显著的优势。试验结果为果农和橄榄汁生产者选择适宜的橄榄品种提供了科学参考。     

以丝胶蛋白为细菌培养基主要成分的研究

通过对分子量小于6万的水溶性丝胶肽或者丝胶肽及其水解物以不同比例替代或完全替换普通液体培养基中主要成分蛋白胨进行的3种代表性细菌的培养试验，说明水溶性丝胶肽及其水解物营养非常丰富，是一种新型的液体培养基主要成分。     

Investigation of Cashew Apple Juice as a Substrate for Single Cell Protein Production

Cashew juice was investigated for its ability to support the growth of Saccharomyces cerevisiae. A characteristic of the juice showed that it contained a mixture of fermentable sugars of which glucose, fructose and sucrose have been identified. Also the concentration of reducing sugars was as high as 15% w/v. Growth studies were carried out in a 7-L batch fermentor at a pH of 5.0 and 30°C with and without nutrient supplementation. The corresponding yields were 0.50 and 0.39 gram cells/gram reducing sugar consumed, respectively. While about 10% of the reducing sugar was consumed in the unsupplemented medium 43% was consumed in the medium with supplementation.     

Changes in Volatile Components of Passion Fruit Juice as Affected by Centrifugation and Pasteurization

Volatile components of fresh passion fruit (hybrid variety, cultivar Tai-Non No. 1) juice (A), de-starched juice (B), pasteurized and destarched juice (C) and headspace volatiles that were recovered during centrifugation of fresh juice (D) were compared. Charcoal adsorption was used to recover the headspace compounds. The yields of volatiles obtained from the different treatments were 31.69 mg/kg juice for A, 18.97 mg for B, 12.27 mg for C, and 7.93 mg for D, respectively. The pasteurization process (1 min at 85°C) caused a 35% loss in volatile components.     

Improved Feed Protein Fractionation Schemes for Formulating Rations with the Cornell Net Carbohydrate and Protein System

Adequate predictions of rumen-degradable protein (RDP) and rumen-undegradable protein (RUP) supplies are necessary to optimize performance while minimizing losses of excess nitrogen (N). The objectives of this study were to evaluate the original Cornell Net Carbohydrate Protein System (CNCPS) protein fractionation scheme and to develop and evaluate alternatives designed to improve its adequacy in predicting RDP and RUP. The CNCPS version 5 fractionates CP into 5 fractions based on solubility in protein precipitant agents, buffers, and detergent solutions: A represents the soluble nonprotein N, B1 is the soluble true protein, B2 represents protein with intermediate rates of degradation, B3 is the CP insoluble in neutral detergent solution but soluble in acid detergent solution, and C is the unavailable N. Model predictions were evaluated with studies that measured N flow data at the omasum. The N fractionation scheme in version 5 of the CNCPS explained 78% of the variation in RDP with a root mean square prediction error (RMSPE) of 275 g/d, and 51% of the RUP variation with RMSPE of 248 g/d. Neutral detergent insoluble CP flows were overpredicted with a mean bias of 128 g/d (40% of the observed mean). The greatest improvements in the accuracy of RDP and RUP predictions were obtained with the following 2 alternative schemes. Alternative 1 used the inhibitory in vitro system to measure the fractional rate of degradation for the insoluble protein fraction in which A = nonprotein N, B1 = true soluble protein, B2 = insoluble protein, C = unavailable protein (RDP: R² = 0.84 and RMSPE = 167 g/d; RUP: R² = 0.61 and RMSPE = 209 g/d), whereas alternative 2 redefined A and B1 fractions as the non-amino-N and amino-N in the soluble fraction respectively (RDP: R² = 0.79 with RMSPE = 195 g/d and RUP: R² = 0.54 with RMSPE = 225 g/d). We concluded that implementing alternative 1 or 2 will improve the accuracy of predicting RDP and RUP within the CNCPS framework.     

Generation,Fractionation, and Characterization of Iron‐Chelating Protein Hydrolysate from Palm Kernel Cake Proteins

Palm kernel cake protein was hydrolyzed with different proteases namely papain, bromelain, subtilisin, flavourzyme, trypsin, chymotrypsin, and pepsin to generate different protein hydrolysates. Peptide content and iron‐chelating activity of each hydrolysate were evaluated using O‐phthaldialdehyde‐based spectrophotometric method and ferrozine‐based colorimetric assay, respectively. The results revealed a positive correlation between peptide contents and iron‐chelating activities of the protein hydrolysates. Protein hydrolysate generated by papain exhibited the highest peptide content of 10.5 mM and highest iron‐chelating activity of 64.8% compared with the other hydrolysates. Profiling of the papain‐generated hydrolysate by reverse phase high performance liquid chromatography fractionation indicated a direct association between peptide content and iron‐chelating activity in most of the fractions. Further fractionation using isoelectric focusing also revealed that protein hydrolysate with basic and neutral isoelectric point (pI) had the highest iron‐chelating activity, although a few fractions in the acidic range also exhibited good metal chelating potential. After identification and synthesis of papain‐generated peptides, GGIF and YLLLK showed among the highest iron‐chelating activities of 56% and 53%, whereas their IC₅₀ were 1.4 and 0.2 μM, respectively.     

Evaluation of Sesame Flour as a Complementary Protein Source for Combinations with Soy and Corn Flours

Sesame products in combination with soy flour, were evaluated as a protein source. Proximate analyses, microbiological examination, determination of vitamins, minerals, selenium content, and nutritional evaluation were carried out. Monagas Aceitera variety flours are similar to other sesame proteins in composition but are higher in lysine and methioine. Enrichment with soy increased PER value for all sesame products. At commonly used fortification levels, sesame-soy blends may be as useful as soy alone for addition to corn-based foods. Some sesame flours and isolates might contain toxic amounts of selenium.     

果胶酶催化条件及澄清果汁的研究

本试验以本系分离选育的果胶酶菌种为试验菌种。在摸清最适作用温度和pH的前提下,研究证实所提供的四种酶(X_1、X_2、Y_2、Y_3)对苹果醋,桔子汁、苹果汁、山楂汁、樱桃汁和草莓汁等均有明显的澄清作用,而对梨汁、西瓜汁等澄清作用不明显。其中,Y_2对苹果醋和苹果汁澄清作用最好,其次为X_1、X_2、Y_3;X_2对山楂汁澄清作用最好,其次为X_1、Y_2和Y_3;Y_3和X_2对桔子汁澄清作用最好,X_1和Y~2次之;Y_2、X_1、X_2对草莓汁澄清作用最好,Y_3次之。