Rapid Extraction of Pawpaw Juice with the Application of Locally Produced Pectic Enzymes from Saccharomyces Cerevisiae ATCC 51712

Pawpaw (Carica papaya) fruit is highly perishable; hence, conversion into a value-added product such as juice concentrate will be useful. Pawpaw fruit is, however, high in pectin; therefore, its juice extraction is difficult without an extraction aid such as the addition of pectic enzymes. Our laboratory has developed a simple enzymatic method that enables the extraction of pawpaw juice with considerable ease. Pectic enzymes were obtained from Saccharomyces cerevisiae (ATCC 52712) cultured in pawpaw juice for 6 days at room temperature (25–28°C) and centrifuged to obtain the enzyme in the supernatant. Addition of this enzyme (32 mg total protein) to 200 g pawpaw mash and incubation for 30 min resulted in significant (P < 0.05) reduction in the viscosity of the mash with corresponding increases in the flow rate of free-run juice (85%). Simultaneously, large increases in the volume of free-run juice (180%) over the controls were obtained. Since the overall increase in total juice volume was only 35% as compared with 180% for volume of free–run juice and 80% increase in flow rate for free–run juice, it was concluded that the major effect of the enzyme treatment on pawpaw juice extraction is on the decrease in processing time as a result of the degradation of the pectin in the fruit flesh.     

High-Intensity Ultrasound Processing of Pineapple Juice

The influence of ultrasound processing on the physicochemical characteristics of pineapple juice was investigated through an experimental design changing ultrasound time and intensity. After processing, the polyphenoloxidase (PPO) activity in the pineapple juice was reduced by 20% as result of the treatment with longer exposure and higher intensity (376 W/cm² and 10 min). The effect on phenolic compounds compared to the fresh pineapple juice (non-sonicated) was not statistically significant. Ultrasound processing reduced juice viscosity by 75% of the initial value (non-sonicated juice). The higher the ultrasound intensity and the juice exposure (processing time), the higher the final temperature of the juice, reaching a maximum of 54 °C. Ultrasound processing enhanced the juice color and its stabilization along 42 days of storage compared to the non-sonicated juice. Thermal treatment at the highest temperature reached due to juice sonication (54 °C) showed no effect on PPO inactivation.     

COMBINED EFFECTS OF ENZYME DOSAGE AND REACTION TIME ON PAPAYA JUICE EXTRACTION WITH THE AID OF PECTIC ENZYMES – A PRELIMINARY REPORT

Pectic enzymes are widely used in the food industry for fruit juice extraction as well as in the clarification of cloudy juices. Our laboratory has been using pectic enzymes produced from a strain of Saccharomyces cerevisiae (ATCC 52712) in different applications including fruit juice extraction. The enzyme was produced in the laboratory by culturing the yeast in papaya juice supplemented with 1% pectin for 6 days. Known amounts of enzyme preparation (0–40 mg protein) were added to a measured weight of papaya mash for varying reaction periods (30–90 min) and the amount of free‐run juice obtained in each treatment compared with a control sample. Treatment of 200 g of papaya mash with different dosages of the pectic enzyme extract resulted in rapid increases in flow rate of free‐run juice. Mash treated with 32 mg of total protein extract with a 30‐min reaction time was the optimum for a maximum rate of juice flow (25 mL/min) when initial rates were measured. There was no significant difference (P > 0.05) between the red‐ and yellow‐fleshed varieties of the papaya used. When juice flow was monitored over 6 min, the treated samples gave a flow rate that was more than twice those of the untreated samples. This biotechnological approach could be adopted to enhance papaya‐juice production by local fruit juice processors when parameters for scale‐up processes are established.     

Comparative study of juice production by pulsed electric field treatment and enzymatic maceration of apple mash

The application of pulsed electric fields (PEF) to apple mash as an alternative to enzymatic mash maceration (EM) was investigated on a pilot plant scale. Chemical composition of the juices obtained by different processes was similar, except for phenolic content and antioxidative capacity, thus proving substantial equivalence of the juices. However, PEF led to an enhanced release of nutritionally valuable phenolics into the juice. Sensory properties of the juices did not significantly differ when PEF pre-treatment was applied. Total juice yield amounting to approx. 85% was not increased by PEF treatment and was irrespective of the different mash pre-treatments, however, juice release was delayed after PEF application (W = 10 kJ/kg), whereas EM enhanced the de-juicing process. In contrast to EM, genuine pectin quality was retained by PEF processing, which allows sustainable pomace utilisation and additional commercial benefit through its commercialisation. Within a storage time of 40 weeks juice composition remained unchanged.     

果蔬汁与蛋白酶联合作用对原料牛肉的质构特性和色泽影响

利用果蔬汁和蛋白酶对原料牛肉进行联合处理,研究处理前后原料牛肉的质构特性和色泽的变化。研究结果表明,菠萝汁和中性蛋白酶联合处理,与对照组和其它五种果蔬汁和蛋白酶处理组相比,可显著地提高原料牛肉的嫩度,减低其硬度,但处理后原料牛肉的内聚性和胶着性也降低最大,而其色泽基本不变。菠萝汁和中性蛋白酶联合作用原料牛肉的最佳处理条件:混合处理液总浓度(菠萝汁和中性蛋白酶组成比例为3∶1)6%,pH7.0,作用温度50℃。      

菠萝汁对牛肉的嫩化效果研究

以菠萝汁和牛肉为原料,研究菠萝汁中菠萝蛋白酶对牛肉的嫩化作用,得到了嫩化的最佳工艺：菠萝汁浓度6%、时间60min、温度50℃、pH7.0。在此条件下,牛肉剪切力可降低50% 左右。对菠萝汁、生姜汁、木瓜蛋白酶嫩化产品与对照组进行了风味、色泽、剪切力的对比,结果表明：菠萝汁较生姜汁能够显著(p ≤ 0.05)提高产品的风味,相比木瓜蛋白酶及对照组其风味也有不同程度提高;菠萝汁、生姜汁、木瓜蛋白酶都能极显著(p ≤ 0.01)的提高产品的嫩度,而三种嫩化产品之间嫩度没有显著差异;用菠萝汁嫩化牛肉,在牛肉腌制后,其色度的b 值和a/b 值相对于对照组有极显著(p ≤ 0.01)提高,而在煮制后,只有b 值和对照组有显著(p ≤ 0.05)差异,而a/b 值无显著差异,表明用菠萝汁嫩化牛肉不会对产品的色泽造成不良影响。     

Statistically designed two step response surface optimization of enzymatic prepress treatment to increase juice yield and lower turbidity of elderberry juice

This study examined the effects of different, statistically designed, enzymatic maceration treatments on juice yield, turbidity, and phenol yield (total phenols and total anthocyanins) in experimentally produced elderberry juice. Increased pectinolytic enzyme dose, longer maceration time, and elevated reaction temperature all had significantly positive effects on the juice yield. Increased enzyme dose and maceration temperature also increased the yields of anthocyanins in the elderberry juice, while none of the reaction parameters affected the juice turbidity. The juice yield was optimized further in a new experimental template, made by using the statistical steepest ascent optimization method. In the new response surface design template an optimal maceration treatment giving maximal juice yield and anthocyanin yields and low turbidity was identified. With the optimal treatment with a pectinolytic enzyme preparation, Pectinex BE 3L, produced by a cloned Aspergillus strain, a maximal juice yield of 77% w/w of the berry mash, an anthocyanin yield of 2380 mg/kg fresh berry mash, and a turbidity level of 128 formazin nephelometric units (FNU) were obtained. Enzymatic prepress treatment generally decreased turbidity levels by 30% as compared to pressing without prior enzymatic treatment. A comparison of the responses obtained after the optimal enzymatic treatment with five different pectinolytic enzyme preparations showed that the Aspergillus niger preparation Pectinex BE Color gave slightly better juice and phenol yields, and lower turbidity levels than the other enzyme preparations tested. In conclusion, the results demonstrated that juice yields and phenolic yields in elderberry juice could be improved with enzyme treatment and that the optimal reaction conditions for obtaining the best juice yield, highest phenolics, and lowest turbidity levels could be rationally identified via statistical factor level optimization.Industrial relevanceThis paper describes an optimization study on enzymatic pre-press treatment of elderberries for elderberry juice production. The aim is to increase juice yield, lower juice turbidity, and enhance the release of anthocyanins and other co-existing phenolics into the juice via enzyme catalyzed degradation of the cell wall polysaccharides in the elderberries. The work defines an optimal enzymatic treatment for increased elderberry juice yield, anthocyanin yield, and lowered juice turbidity, and also demonstrates how to shift a statistical design template to obtain improved results on selected parameters. Although the work is focused on elderberry juice the enzymatic as well as the statistical design strategy can easily be adapted for other fruit juice and food processes.     

壳聚糖对菠萝汁澄清作用的影响

果汁加工的关键技术是果汁的澄清技术,因此应用壳聚糖对菠萝汁进行了澄清,研究结果表明在最佳pH、温度、澄清时间的条件下,0.1 g/L~1.0 g/L壳聚糖澄清菠萝汁,其透光率可达80%以上,且岀汁率有明显提高,较彻底地清除了影响菠萝汁澄清度的蛋白质和果胶,使得菠萝清汁的贮存稳定性大大提高。     

THE USE OF PULSED ELECTRIC FIELDS IN PRODUCING JUICE FROM PAPRIKA (CAPSICUM ANNUUM L.)

Investigations were conducted on the impact of pulsed electric field (PEF) treatment on yield and some quality parameters of juice from paprika and results were compared to the results of juice obtained from enzymatically treated or untreated paprika mash. Paprika was comminuted mechanically after which the mash was subjected to either PEF (electric field strength = 1.7 kV/cm, pulse number = 30 and specific energy input per pulse = 0.5 kJ/kg) or a pectolytic enzyme preparation treatment. The extent of cell disintegration after the different pretreatments was monitored through cell disintegration index (Z_p) measurement prior to juice extraction through pressure (10 MPa for 4 min). Some quality parameters (pH, soluble solids (°Brix), total dry matter, color, total carotenoids as β-carotene and vitamin C) of the resultant juice samples were determined. PEF and enzyme treatments resulted in about 10% and 9% increase in juice yield, respectively. Juice from PEF treated paprika compared well in quality with enzyme treated or the untreated. And in some cases such as in color (redness, a value) of the juice, PEF treated had values (+ 18) higher than enzyme treated having + 15.5 and also in the amount of β-carotene extracted into the juice PEF treated juice had more than 60% as compared to about 44% from enzyme treated juice. The pH value for enzyme treated juice was lower than the others.     

菠萝汁酶解大豆多肽发酵酸豆乳的研制

利用菠萝汁中所含蛋白水解酶将豆乳中的蛋白质部分水解成为功能性多肽,再添加乳酸菌发酵剂制成酸豆乳。酶解条件的优选采用L9(34)正交实验法,以蛋白质水解度为评价指标,确定最佳酶解条件为:菠萝汁用量15%;pH=7.0;温度45℃;时间70 min。发酵豆乳产品的配方设计采用L9(34)正交实验,以感官品评分数为评价指标,确定最佳的产品配方为:蔗糖含量4%;乳粉含量3%;豆水比1∶4;稳定剂0.5%。     

超高压处理对菠萝汁中菠萝蛋白酶纤溶活性的影响

为保留菠萝汁中菠萝蛋白酶的纤溶活性,探讨了超高压处理中压力、保压时间和温度对菠萝蛋白酶纤溶活性的影响,并考察其在模拟胃肠道环境中的稳定性。结果表明:压力、保压时间和温度均对菠萝汁中菠萝蛋白酶纤溶活性的影响显著,压力300MPa、温度30℃、保压10min时菠萝蛋白酶的纤溶活性比未处理样高65.54%;300MPa保压10min(30℃)处理的菠萝汁在模拟胃液和肠液各处理4h后,纤溶活性残留率分别为37.91%和85.33%,均高于鲜榨汁。说明,通过调整超高压处理条件,可以提高菠萝汁中菠萝蛋白酶的纤溶活性及其对模拟胃肠液的耐受性。      

Enzymatic Browning Inhibited in Fresh and Dried Apple Rings by Pineapple Juice

Sliced apple rings were treated with water (control), canned pineapple juice, frozen pineapple juice, ion-exchanged pineapple juice, frozen orange juice, ascorbic acid, a commercial antibrowning preparation or sodium bisulfite. The rings were either left exposed to air, vacuum packaged, or dehydrated. Browning was measured calorimetrically and by visual examination over extended periods of time. Pineapple juice was an effective browning inhibitor in both fresh and dried apples. Pineapple juice was fractionated using various size and charge separation procedures. All fractions inhibited enzymatic browning of crude apple extracts by at least 26%. Results indicate that the inhibitor is a neutral compound of low molecular weight.     

Effect of cassava starch coating on quality and shelf life of fresh-cut pineapple (Ananas comosus L. Merril cv "Pérola")

This research studied the influence of treatment with ascorbic acid, citric acid, and calcium lactate dipping and cassava starch edible coatings on quality parameters and shelf life of fresh-cut pineapple in slices during 12 d at 5 °C. After previous tests, the treatments selected for this study were samples dipped into antibrowning solution with 0.5% of ascorbic acid and 1% of citric acid, with and without 2% of calcium lactate and coated with 2% of cassava starch suspensions. Changes in weight loss, juice leakage, mechanical properties (stress at failure), color parameters (L* and H*), ascorbic acid content, sensory acceptance, and microbial growth of fruits were evaluated. Samples only treated with antibrowning agents were used as control. Edible coatings with and without calcium lactate were efficient in reducing weight loss, juice leakage, and maintaining firmness during storage. However, these samples showed more browning and the ascorbic acid content was reduced. All treatments presented good sensory acceptance (scores above 6). The determining factor of shelf life of pineapple slices was the microbial spoilage. A shelf life of 8 d was obtained for pineapple slices only treated with antibrowning agents. On the other hand, coated samples showed a reduced shelf life of 7 d and higher yeast and mold growth. Thus, although cassava starch coatings were efficient in reducing respiration rate, weight loss, and juice leakage and maintained mechanical properties, these treatments were not able to increase the shelf life of minimally processed pineapple. Practical Application: Pineapple fruit is highly appreciated for its aroma, flavor, and juiciness, but its immediate consumption is difficult. Therefore, pineapple is a potential fruit for minimal processing. However, shelf life of fresh-cut pineapple is very limited by changes in color, texture, appearance, off-flavors, and microbial growth. The use of edible coatings as gas and water vapor barrier and antibrowning agents can extend the storage time and maintain the quality of fresh-cut produce. Cassava starch and alginate coatings are alternative to preserve minimally processed pineapples without changing the quality parameters of fresh fruit. Thus, this study is useful for consumers and fresh-cut industry interested in knowing factors affecting shelf life and quality of fresh-cut pineapple.     

菠萝-香蕉复合纯果汁生产工艺及冻藏研究

为了研究菠萝-香蕉复合纯果汁饮料的生产工艺,以菠萝和香蕉为主要原料经打浆、过滤和调配后,添加适量的纯奶,以蔗糖为调味剂配制成复合纯果汁。通过正交试验确定了该复合纯果汁的最佳配方为：菠萝：香蕉为6：1,纯奶添加量为10％,蔗糖添加量为8％,果汁具有色泽美观、甜酸可口和风味独特等特点。但对最佳配方产品进行冻藏试验,发现产品在冻藏期问褐变程度增大,香气变淡,口感略微变差。     

Optimising clarification of carrot juice by bacterial crude pectinase

This study was undertaken to search for potential use of crude bacterial pectinase enzyme produced from Bacillus subtilis grown on hazelnut shell hydrolysate in clarification of carrot juice and to optimize the enzyme load, pH and time using the Box–Behnken response surface methodology (RSM). The carrot juice was treated with the crude pectinase enzyme (5.60 U mL^?1) at different concentrations (0.1–0.5%), pH (4–7), and time (2–6 h). The obtained enzyme was also compared with commercial fungal pectinase at identical conditions. RSM provided optimal clarification conditions of 0.5% (w/v) enzyme load, 7.0 pH, and 6 h of time estimating 100% clarity, whose experimental counterpart was 94.47 ± 0.01%. High values of coefficient of determination (R² = 0.9631), predicted R² (0.8989) and insignificant lack‐of‐fit (0.12) also showed that the model was successful in predicting % clarity for various combinations. This study also indicated that crude bacterial pectinase providing about 95% clarity is superior to commercial fungal pectinase, which gave 78% clarity under tested conditions, in terms of clarification ability for carrot juice.     

Effect of juice processing on the cancer chemopreventive effect of cranberry

Cancer chemopreventive properties were evaluated in cranberries and cranberry products (mash, depectinized mash, pomace, raw juice, clarified juice and juice concentrate). Three extracts isolated from frozen cranberries and cranberry solids (mash, depectinized mash and pomace) containing anthocyanins, water-soluble and apolar phenolic compounds were tested. Cranberry juices and extracts were screened for their ability to induce the phase II xenobiotic detoxification enzyme quinone reductase (QR). The results showed that there was no cytotoxicity against the cells used in the test. All samples stimulated quinone reductase activity except the highest concentrations of the anthocyanin-rich extract of pomace, which inhibited QR activity. Also, the results showed that the QR induction for all samples varied with concentration and that there was an optimal concentration for which the QR induction was maximal. Although the three cranberry extracts were good QR inducers, our results indicated that the phenols present in aqueous extract showed QR inductions which were more important than those obtained with phenols present in solvent extracts. Also, the ability of phenols to stimulate the QR activity has been reduced continuously and significantly (P ≤ 0.05) during the technological process. Especially, it appears that conditions of the evaporation to obtain a juice concentrate exerted a significant effect (P ≤ 0.05) on inducer potencies of bioactive molecules.     

Improving apple juice expression and quality by pulsed electric field on an industrial scale

This study investigated the Pulsed Electric field (PEF) effect on apple mash, regarding quantitative, qualitative and sensory attributes, on an industrial scale. PEF treatment (E = 650 V/cm, t_PEF = 23.2 ms, q = 32 kJ/kg) was applied to apple mash at the flow rate of 4400 kg/h in a module of colinear design made of four treatment chambers.Juice yield significantly increased from 71.1% to 76.3% due to PEF treatment. A significant increase of 8.8% was also observed for the native polyphenols concentration when an inhibitor of the enzymatic oxidation was added. Juice colour was significantly altered by the PEF treatment. The saturation in the yellow rose significantly from 17.9 to 26.8.The juice from treated mash was less turbid and was described by odour intensity and typical odour of apple significantly higher than the untreated sample. Similarly, the overall and typical taste of apple juice were significantly more intense. The chemical composition (Fructose, Glucose and Malic acid) of juice did not vary despite a significant increase of the dry matter for treated samples. On the contrary, a significant depletion of fructose and glucose was noted for the pomace from treated mash as compared to the control.     

Optimization of enzymatic process parameters for increased juice yield from carrot (Daucus carota L.) using response surface methodology

The effects of enzyme concentration (50–650 mg/kg grated carrot), pectolytic and cellulolytic enzyme ratio (3:7–7:3), incubation time (30–150 min) and temperature (25–65 °C) on juice recovery and viscosity from grated carrot were studied. A central composite rotatable design (CCRD) was used in designing the treatment combinations of four variables at five levels. The process involved in treating the blanched grated carrot with mixture of crude pectolytic enzyme from Aspergillus foetidus and crude cellulolytic enzyme from Trichoderma ressi, keeping the samples at the desired time, followed by extraction of juice. Enzyme-treated grated carrot sample showed increased juice recovery as compared to control. A second-order response surface model adequately fitted the data. All the variables affected juice recovery and viscosity significantly. Enzyme concentration, pectolytic and cellulolytic enzyme ratio, incubation time and temperature had total and combined effect at linear, square and interactive level on both responses. The optimum condition was enzyme concentration, 210.7 mg/kg of grated carrot; pectolytic and cellulolytic enzyme ratio, 3.84:6.16; incubation time, 130 min and incubation temperature 47 °C. Under the optimal conditions, juice extracted from enzyme-treated grated carrot was 74.3% having juice viscosity 1.07 cP, corresponding to the increase in yield by 13.95% and decrease in viscosity by 0.45 cP.     

蒲公英、菠萝天然饮料的生产工艺研究

本研究以蒲公英、菠萝为主要原料,加以柠檬酸、蜂蜜等辅料,经科学加工制成具有独特风味和很高营养价值的天然饮料。对蒲公英、菠萝复合保健饮料的生产工艺、配方和技术关键进行了研究。通过正交试验及方差分析,确定出该饮品的最佳组合方式为A3D4C4E2B2即澄清的蒲公英菠萝复合汁45ml,蜂蜜2ml,柠檬酸0.15g、柠檬酸钾0.1g、蔗糖0.3g、水为52.45ml(上述均为质量百分数)。通过实验,还确定出产品最适稳定剂配方:CMC-Na为0.02%。     

THE EFFECT OF ENZYMATIC MASH TREATMENT, PRESSING, CENTRIFUGATION, HOMOGENIZATION, DEAERATION, STERILIZATION AND STORAGE ON CARROT JUICE

The enzyme preparation Pectinex Smash XXL was employed to macerate the carrot pulp, the effect of enzymatic mash treatment (EMT), pressing, centrifugation, homogenization, deaeration, sterilization and storage on carrot juice was investigated. As compared with the control sample, an increase of juice yield, total soluble solid (TSS) and carotenoids in carrot juice was close to 20%, 1% and 26 mg/kg, respectively, after EMT. The EMT also increased the color parameters CIEL*, a*and C*values in carrot juice. However, it significantly decreased the viscosity from 2.54 to 2.09 mPa·s. The centrifugation resulted in a significant decline in turbidity from 240.33 to 187.33 NTU and a significant increase in the color parameters in carrot juice. After homogenization, the turbidity and the carotenoids in carrot juice were significantly reduced from 187.33 to 161.67 NTU and from 61.87 to 58.76 mg/kg, respectively. The turbidity and carotenoids in carrot juice decreased during storage, and all the color parameters had a closer relationship with storage temperature and time; higher storage temperature and longer storage time caused greater loss of color.