Effects of pulsed electric field treatment of apple mash on juice yield and quality attributes of apple juices

The influence of apple mash treatment with pulsed electric fields (PEF) on yield and quality attributes of the resulting cloudy juices were investigated. Apple juice was produced at laboratory scale (400 g apples per lot) by mash treatment with pulsed electric fields at three different field intensities (1, 3, 5 kV/cm, n = 30 pulses) and manual pressing at room temperature. The juices were compared with untreated control juices of the same mash and with a juice after pectolytic mash treatment. Relative to the control samples, juice yield increased with increasing field intensities. The overall composition as described by pH, total soluble solids, total acidity, density, contents of sugar, malic acid and pectin, respectively, as well as the nutritive value with respect to polyphenol contents and antioxidant capacities (TEAC, FRAP, DPPH) of the PEF-treated apple juices did not significantly differ from the controls.Industrial relevanceThis paper addresses the composition of apple juice after mash treatment applying pulsed electric fields and maceration enzymes, respectively. Since substantial equivalence of products derived from novel technologies, such as PEF, relative to their conventionally produced counterparts is required according to European food law, this aspect is of great relevance, especially for commercialisation of fruit juices based on PEF technology. Furthermore, the nutritional value of juices produced at different pulsed electric field activities is of relevance for their marketing.     

Phenolics from purple grape, apple, purple grape juice and apple juice prevent early atherosclerosis induced by an atherogenic diet in hamsters

Knowledge of the effects of processing on the antioxidant properties of fruits is limited. We investigated the processing of apple (A) and purple grape (PG) and their juices (AJ and PGJ) in hypercholesterolemic hamsters. Five groups of eight hamsters each were fed an atherogenic diet for 12 wk. They received daily by gavage either 7.14 mL/(kg x day) of mashed A or PG, or the same volume of AJ or PGJ, or water as control. Plasma cholesterol, non-HDL cholesterol, liver superoxide dismutase and glutathione peroxidase activities, and thiobarbituric acid reactive substances were efficiently reduced by the fruits and their juices compared with controls, whereas plasma antioxidant capacity was increased and aortic fatty streak area was decreased from 48 to 93%. For each of these parameters, the efficacy was PGJ > PG > AJ > A. The results show for the first time that long-term consumption of antioxidants supplied by apple and purple grape, especially phenolic compounds, prevents the development of atherosclerosis in hamsters, and that processing can have a major impact on the potential health benefits of a product. The underlying mechanism is related mainly to increased antioxidant status and improved serum lipid profile.     

苹果法的欧姆加热研究

研究了苹果汁的欧姆加热规律及其对果汁品质的影响,考察了温度(T)和可溶性固形物(SS)含量对电导率σ的影响,以及电场强度(E)、可溶性固形物(SS)和加热体积(液高 h)对加热速率的影响、同时考察了欧姆加热对果汁糖度、pH、透光率等的影响.结果表明,苹果汁的电导率随温度的升高而增大,且呈线性关系,随着可溶性固形物含量的增加,苹果汁的电导率和加热速率都是先增大然后减小,在26°Bx左右时最大.苹果汁的加热速率随电场强度的增加而增大,而在相同电场强度下,液高对加热速率没有影响.并且,欧姆加热对果汁品质影响很小,因此极具开发前景.     

The influence of simple and condensed phenolics on the clarification of apple juice by honey

The rate at which polyphenolics of six apple cultivars were able to flocculate (coagulate) with honey proteins was compared. Condensed tannins were primarily responsible for the formation of the flocculates. The activity of tannins with honey proteins was high in the cultivars Red Delicious, Rome, and McIntosh (group A), and lower for the cultivars Jonathan, Golden Delicious, and Rhode Island Greening (group B). In order to understand the differences in clarification rates by cultivars, model systems were used to estimate the effect of simple polyphenolic compounds on the formation of insoluble tannin/protein complexes. The addition of chlorogenic acid or gallic acid to the systems containing honey proteins and tannic acid resulted in a significant decrease in the rate of formation of flocculates, whereas the addition of catechol to the above systems did not affect the flocculation time of tannic acid with honey proteins. A hypothesis is put forward to explain these results.     

酶法洗渣提高橙汁得率

研究酶法洗渣提高橙汁得率的新工艺。确定了酶法处理橙渣的工艺条件为:加酶量0.01%、渣水比1∶1、酶解温度45℃、酶解时间50min。实验证明,采用此法生产的橙汁能够明显提高出汁率和改善橙汁的产品质量,从而生产出具有良好的混浊稳定性、口味宜人、鲜艳色泽的橙汁。     

The influence of enzymatic treatment of mash on the analytical composition of apple juice

Five apple juices were produced on a pilot scale by crushing the fruit, treating the mash with pectolytic enzymes, pressing, extracting water from the pomace, pasteurization, treatment of the juice with enzymes, combined gelatin/silica sol fining and final ultrafiltration. The temperature of the mash treatment was either ambient or one of 30, 40, 50 or 60 °C, in order to test whether this led to different compositional changes in the corresponding juices. The main emphasis was put on detection of D -galacturonic acid as the indicator substance for the extent of the enzymatic treatment. In the pasteurized raw juices after pressing we found values from 226 to 398 mg L⁻¹. A distinct increase of the galacturonic acid levels could be observed during the clarification steps. Enzymatic juice treatment raised the concentrations to 580–720 mg L⁻¹. After ultrafiltration, final values of 790–1100 mg L⁻¹ were measured. Generally, the highest values were found in the 50 °C sample, which is the optimum temperature for pectinase activity. This was also true for the colloid concentrations and polyphenols. The influence of the temperature of the enzymatic mash treatment on other characteristic juice parameters like total titratable acidity, density, sugar, and minerals concentrations was low.     

微波萃取技术在天然食用色素提取上的应用

微波辐射提取技术与传统加热提取技术相比，具有提取时间短、温度低、耗能低、品质高等优良特性。采用该技术提取天然食用色素的实际结果表明，微波提取技术是一种有良好发展前途的新工艺，有利于工业化生产。     

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.     

The influence of pectolytic enzyme addition and prefermentative mash heating during the winemaking process on the phenolic composition of Okuzgozu red wine

The effects of pectolytic enzyme addition and mash heating prior to fermentation on the phenolic component of Okuzgozu red wine during the winemaking and ageing processes were investigated. In general, the highest concentration of total phenolics was found in the mash-heated wines, whereas the total flavan-3-ol and total anthocyanin contents in all of the wines, decreased notably during the winemaking and ageing processes. As determined by HPLC, hydroxycinnamic acids were the major phenolic acids in the red wines. After 6 months in the bottle, the enzyme-treated wines had lower phenolic acid concentrations than had the control and mash-heated wines, but no significant (p < 0.05) differences were found in the concentration of total phenolic acids between the control and mash-heated wines. All of the phenolic acid levels decreased with the winemaking and ageing processes whereas only gallic acid increased. The wines treated by the pectolytic enzyme addition had a lower monomeric flavan-3-ol content than had the other wines, and the amount of monomeric anthocyanins extracted did not increase with the addition of enzymes.     

微波辅助提取技术在天然产物提取中的应用

与天然产物的传统提取方法比较,微波辅助提取技术具有方便、省时、能耗少等优点,受到广大研究人员的注意。本文综述微波辅助提取技术在天然产物提取中的应用及存在的一些问题。     

改善茶饮料品质的工艺探讨

根据茶饮料的特点,从生产工艺的角度来饮料的品质。     

微波预处理法提取番茄皮中番茄红素的工艺研究

本实验研究了微波预处理法提取番茄皮中番茄红素的提取工艺条件,探讨了浸润溶剂用量、液料比、微波预处理时间、微波功率对番茄红素提取效果的影响。本实验最佳提取工艺条件:浸润溶剂用量为8ml,液料比为8∶1,微波功率720w,微波预处理60s。     

微波、纤维素酶预处理对大豆低聚糖提取的影响

以脱脂豆粕为原料,在碱液浸提法提取大豆低聚糖的最佳工艺条件(在55℃和pH为11的条件下浸提1h)的基础上,采用微波和纤维素酶分别对脱脂豆粕进行预处理,考察两种方法对大豆低聚糖提取率的影响。实验结果表明:微波处理后大豆低聚糖的提取率有所下降,而经纤维素酶处理后,低聚糖的提取率有显著提高。     

Grape marc phenolics: Extraction kinetics,quality and stability of extracts

The solid–liquid extraction of phenolic compounds from different vintage marcs with 60% ethanol was studied and experimental data were elaborated according to the different mathematical models applied in literature to recovery of bioactive constituents from plant materials. A first-order kinetics model was finally selected and the total phenolics diffusivities were calculated (1.23–1.50 × 10⁻¹⁰ m² s⁻¹).     

桔黄色素微波萃取的研究

研究了影响微波萃取桔黄色素的各项因素及萃取的桔黄色素品质。试验表明 :桔皮含水量为 35 % ,颗粒大小为 6 0目 ,4 0倍桔皮的乙醇为溶剂 ,10min的微波萃取作用下所得桔皮色素不仅收率最高 ,而且性能稳定 ,质量较好。     

Degradation of carotenoids in orange juice during microwave heating

Degradation of carotenoids in orange juice was monitored during microwave (MW) heating at different time/temperature conditions. Various carotenoids were identified and quantified by HPLC. Degradation rate of carotenoids was influenced by MW heating temperatures: at 60 °C and 70 °C for 10 min violaxanthin and antheraxanthin were the compounds most unstable, while lutein and provitamin A carotenoids were more stable. At 85 °C a decrease of about 50% was observed for almost all carotenoids after 1 min of MW heating. Temperature sensitivity (z value) for total carotenoids was 14.2 °C, for single compounds z values ranged between 10.9 °C for β-carotene and 16.7 °C for antheraxanthin. These results can indicate an adequate choice temperature conditions for the quality control of carotenoids and the related nutritional values during MW treatment of orange juices.     

微波技术在调味品中的应用

微波技术应用于调味品行业能大大提高调味品的品质。本文介绍了微波技术的原理和特点，着重阐述微波技术在调味品中的四个应用，促热反应制备调味料、干燥、杀菌、萃取。     

Safety and quality assessment during the ozonation of cloudy apple juice

Traditionally, ozone processing within the food industry has focused on solid foods by either gaseous treatment or washing with ozonized water. However, with the FDA's approval of ozone as a direct additive to food, the potential for liquid applications has emerged. This study investigates the effect of ozone processing on microbial inactivation (E. coli ATCC 25922 and NCTC 12900) and quality parameters (color, phenolic content) of cloudy apple juice. Apple juice samples were ozonated at room temperature (20 ± 1.5 °C) with a generated ozone concentration of 0.048 mg O(3) at a constant flow rate of 0.12 L/min and treatment time of 0 to 10 min. E. coli inactivation kinetics in apple juice were described quantitatively by using the Shoulder log-linear and the Weibull model. Ozone treatment of E. coli in apple juice demonstrate that a desired 5 log reduction can be achieved within 5 min. Apple juice color (L*, a*, and b*) and total phenols were significantly affected by ozone concentration and treatment time.     

Effect of enterocin AS-48 in combination with high-intensity pulsed-electric field treatment against the spoilage bacterium Lactobacillus diolivorans in apple juice

Enterocin AS-48 was tested in apple juice against the cider-spoilage, exopolysaccharide-producing strain Lactobacillus diolivorans 29 in combination with high-intensity pulsed-electric field (HIPEF) treatment (35 kV/cm, 150 Hz, 4 μs and bipolar mode). A response surface methodology was applied to study the bactericidal effects of the combined treatment, with AS-48 concentration and HIPEF treatment time as process variables. At subinhibitory bacteriocin concentrations, microbial inactivation by the combined treatment increased as the bacteriocin concentration and the HIPEF treatment time increased (from 0.5 to 2.0 μg/ml and from 100 to 1000 μs, respectively). Highest inactivation (4.87 logs) was achieved by 1000 μs HIPEF treatment in combination with 2.0 μg/ml AS-48. While application of treatments separately did not protect juice from survivors during storage, survivors to the combined treatment were inactivated within the following 24 h of storage, and the treated samples remained free from detectable lactobacilli for at least 15 days at temperatures of 4 °C as well as 22 °C. The combined treatment could be useful for inactivation of exopolysaccharide-producing L. diolivorans in apple juice.     

Degradation compounds of carotenoids formed during heating of a simulated cashew apple juice

The influence of organic acid and heating treatments on carotenoid degradation on a simulated cashew apple juice was assessed by high performance liquid chromatography coupled with a photodiode array and mass spectrometry detectors. A total of nineteen carotenoids were separated in unheated simulated cashew apple juice, with all-trans-β-cryptoxanthin and all-trans-β-carotene as the major ones. As a consequence of heating, five xanthophylls disappeared, whereas two new cis isomers and five epoxide or furanoid-derivatives were formed and the levels of all cis isomers increased. In addition, 12′-apo-β-carotenal was formed at 90 °C. Two oxidation compounds (12′-apo-β-carotenal and 5,6-epoxy-β-cryptoxanthin) were formed after β-cryptoxanthin heating at 90 °C in an aqueous-based system. In all systems, the amounts of total carotenoids lost were not compensated by those formed. These facts indicated that isomerisation and oxidation to both coloured and non-coloured compounds were the main reactions occurring during heating of carotenoids in aqueous-based and juice systems.