黑果腺肋花楸果汁饮料研制及其品质与抗氧化性评价

为研制黑果腺肋花楸果汁饮料并探究其抗氧化活性,以黑果腺肋花楸果实为主要原料,添加蔗糖、柠檬酸和β-环糊精等辅料,以感官评分为指标,通过单因素实验和正交试验确定黑果腺肋花楸果汁饮料的最佳配方为:黑果腺肋花楸浸提汁用量60%,60%蔗糖糖浆添加量10%,2%柠檬酸溶液添加量2.0%,1% β-环糊精添加量3.0%,该配方所制得的饮料感官评分可达94.5分,其富含16种氨基酸,总量达到374.79 μg/mL,具有黑果腺肋花楸果实的特征香气,色泽均一明亮,风味协调爽口,质地均匀;体外抗氧化活性研究表明:该饮料对DPPH自由基清除率、羟自由基清除率、ABTS+自由基清除能力以及总还原能力分别为36.42%、32.58%、0.54 mmol/L和0.289,说明其具有较好的抗氧化能力。本实验结果为黑果腺肋花楸功能性饮料的开发提供了理论依据。     

The influence of natural sweetener (Stevia rebaudiana Bertoni) on bioactive compounds content in chokeberry juice

The aim was to determine the differences in nutritional quality between chokeberry juices sweetened with sucrose and green stevia powder. The quality of chokeberry juices during refrigerated storage was studied. Chokeberry juices with added green stevia powder had the higher content of analyzed bioactive compounds in comparison with juice samples sweetened with sucrose; vitamin C content increased up to two times, total phenol content up to 6% and antioxidant capacity for 3%. The content of studied bioactive compounds and antioxidant capacity during storage in period of 30 and 60 days was significantly reduced with the exception of steviol glycosides which content was not significantly reduced during the storage period.

Practical applications

Chokeberry juice is a popular, widespread product of chokeberry fruit characteristic for the dark intense red color, slightly unpleasant, bitter taste and extremely rich bioactive compounds content. Because of high nutritional quality, chokeberry juice is often consumed but with the biggest barrier of characteristic astringent taste which can be diminished by addition of sweetener. Producers often combine a low‐cost sweeteners like sucrose which shows numerous negative effects on human health. A good alternative to the sucrose and artificial sweeteners are natural sweeteners extracted from the plant material like steviol glycosides. Except sweetness, stevia products like green powder shows beneficial effect on the bioactive compounds content in the juices sweetened with it. Juices sweetened with stevia shows increased content of bioactive compounds, so such product may represent quality product from category of functional food.     

Phytochemical profile of a blend of black chokeberry and lemon juice with cholinesterase inhibitory effect and antioxidant potential

In this study, black chokeberry concentrate was added (5% w/v) to lemon juice, since previous reports suggested potential health benefits of this blend. The phytochemical composition, antioxidant capacity (scavenging of DPPH, superoxide and hydroxyl radicals, and hypochlorous acid), and inhibitory activity against cholinesterase of the new blend were determined and compared with those of lemon juice and chokeberry in citric acid (5%). The chokeberry concentrate, rich in cyanidin-glycosides, quercetin derivatives, and 3-O-caffeoylquinic acid, and lemon juice, possessing flavones, flavanones, quercetin derivates, and hydroxycinnamic acids, were characterised. The new drink showed a higher antioxidant effect than the chokeberry or lemon controls for all the tested methods, except for hypochlorous acid, in which lemon juice displayed higher activity. Both the lemon juice and chokeberry controls inhibited acetylcholinesterase and butyrylcholinesterase, and this effect was increased in the new mixtures. The results of the different radical scavenging assays indicate that the lemon–black chokeberry (5% w/v) mixture was more antioxidative than the respective controls separately. Moreover, their inhibition of cholinesterase is of interest regarding neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, or senile dementia.     

Structural Impact of Osmotically Pretreated Freeze-Dried Strawberries 0n Their Mechanical Properties

The paper investigates the impact of osmotic dehydration on the mechanical properties (i.e., structural changes and shrinkage) of freeze-dried strawberries. In the research, Senga Sengana strawberries were osmotically dehydrated in sucrose, glucose solution, and starch syrup and subjected to freeze-drying. The osmotic dehydration process strengthened the fruit structure by increasing their cell wall thickness. Osmotic pre-treatment limited the shrinkage of the strawberries by about 50%, while the compression force required for 25% deformation of the dried material was almost 2–963 times greater in comparison to the fruit not subjected to osmotic dehydration, dependent on the type of osmotic solution used.     

Osmotic-Convective Dehydrofreezing Process for Drying Kiwifruit

Osmotic and convective dehydrofreezing were studied to determine sugar concentration, ascorbic acid loss, and texture changes in dried and dehydrofrozen kiwifruit. Two concentrations of sucrose (60° and 72° Brix) were used as osmotic solutions after convective air drying. Time needed to reach desired moisture was reduced with combined drying compared with osmotic drying. Firmness was evaluated by the maximum force from a back extrusion test. A reduction in maximum force was observed after freezing, as compared with fresh and dried fruit. Addition of ascorbic and citric acid as antioxidants in the osmotic solution prevented browning, and significant loss of ascorbic acid during osmotic drying. Air drying at 30°C produced distinguishable color changes.     

Frozen Wild Blueberry-Tofu-Soymilk Desserts

Both wild (lowbush) blueberries (Vaccinium angustifolium Ait.) and soybeans (Glycine max L.) possess a variety of antioxidants, and both foods appear to have multiple health benefits. Our objectives were to identify whether wild blueberry juice concentrate was more acceptable than puree in frozen desserts with a soy milk‐tofu base; to determine whether fat‐free products were as acceptable as those with 10% added fat; and to compare several levels of blueberry juice concentrate. Four frozen dessert formulations were prepared in duplicate from soy milk, silken tofu, sucrose, stabilizer, BJC or puree, soybean oil or polydextrose, sweetened dried blueberries, salt, and lemon juice. Samples were assayed for total anthocyanins, antioxidant activity using the DPPH method, color, overrun, and solids. Fifty‐five persons evaluated the samples using a 9‐point hedonic scale for color, flavor, texture, and overall acceptability. Samples containing blueberry juice concentrate were darker and less blue. Anthocyanin levels were highest in the puree sample and the fat‐free product with 7.8% blueberry juice concentrate. However, antioxidant activity was highest (28 Trolox equivalents per gram) in the samples made with soybean oil and 7.4% blueberry juice concentrate. The puree formulation received higher hedonic scores than did the low‐fat blueberry juice concentrate formulations. The puree formulation received overall acceptability scores of like very much or like extremely by 45% of the consumers. These findings may aid processors in defining potential formulations that combine 2 healthful food ingredients.     

超声和渗透预处理对干燥草莓片品质及抗氧化活性影响

研究蔗糖、果糖、葡萄糖以及蔗糖结合超声渗透预处理对真空冷冻联合热风干燥草莓片品质及其抗氧化活性影响。结果表明:经预处理后干燥草莓片的品质、花色苷、总酚、黄酮、Vc含量和抗氧化能力均有显著性差异(p0.05),其中蔗糖结合超声前处理水分含量最低,硬度最高,而经蔗糖渗透处理的草莓片干燥后色泽与新鲜草莓最接近,a*最高;干燥后草莓片的花色苷、总酚和黄酮含量均高于鲜样,但Vc含量大大降低,其中经蔗糖结合超声预处理后的草莓片花色苷、总酚和黄酮含量最高,分别为22.68 g/L、7.52 mg/g、10.38 mg/g,其对-OH和DPPH清除率也高于其他组,但渗透和超声处理并不能提高草莓片Vc含量和铁离子还原能力;三种糖渍处理均能提高干燥草莓片品质,且蔗糖效果最佳。综上,渗透以及蔗糖结合超声预处理后草莓片品质以及抗氧化活性成分含量较高、抗氧化活性较强,适宜于草莓片的干燥。     

OSMOTIC DEHYDRATION OF STRAWBERRIES IN A BATCH RECIRCULATION SYSTEM

Physical and chemical characteristics of two cultivars of strawberries during osmotic dehydration in sucrose and glucose solutions were investigated. Temperature was found to have a significant effect on the water and sugars (glucose, fructose and sucrose) exchange between strawberry and the osmotic solution. Mass transfer was found not to be significantly different between cultivars. Glucose gain was found to be higher than sucrose for the strawberries osmotically dehydrated in glucose and sucrose solutions at the same mole fraction, respectively. Sugars other than the osmotic sugar were found to decrease in concentration during the osmotic process. The combination of 63% sucrose solution with 25C process temperature for 2 h was able to remove more than 40% of moisture and load less than 0.1% of sucrose in the strawberries.     

不同小分子糖渗透草莓的传质动力学及对真空冷冻干燥草莓品质的影响

为系统地了解不同小分子糖特别是低聚糖和糖醇对草莓的渗透行为以及不同小分子糖对真空冷冻干燥草莓品质的影响,本研究利用两种数学模型对10 种常见小分子糖（白利度为40 °Brix）的渗透动力学进行拟合,并进一步对渗糖处理后真空冷冻干燥草莓的理化特性进行表征。结果表明,Weibull模型更适用于描述渗糖处理后草莓的可溶性固形物增量（solid gain,SG）,而Peleg模型可以更好地描述草莓的水分去除量（water loss,WL）。经不同糖渗透处理结束后,草莓的SG差异较大,山梨糖醇可以使草莓的SG达到6.84 g/100 g,是低聚异麦芽糖的6.16 倍。此外,渗糖处理的草莓硬度得到普遍提高（94.58%～223.23%）;葡萄糖、果糖、山梨糖醇渗透处理组的脆度分别降低了16.70%、20.74%、41.45%,低聚果糖渗透处理后的草莓质构特性与蔗糖最为接近。综合考虑渗透效率、感官营养品质和生产成本,低聚果糖是蔗糖在果蔬渗透处理方面的一种潜在替代品。     

Effects of drying methods on contents of bioactive compounds and antioxidant activities of black chokeberries (<Emphasis Type="Italic">Aronia melanocarpa</Emphasis>)

Optimal drying techniques for maintaining high levels of bioactive compounds and antioxidant activities in black chokeberries were investigated. Effects of 3 drying methods on total bioactive compound contents and in vitro antioxidant activities in 80% ethanol extracts were evaluated. Fresh black chokeberries were dried using sun-drying, freeze-drying, and oven-drying. Highest amounts of total polyphenols, flavonoids, and anthocyanins were detected in freeze-dried black chokeberry extracts after sun and oven-drying. 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and superoxide anion scavenging activities in black chokeberry extracts were also evaluated. Freeze-dried berries produced strongest antioxidant activities. Freeze-drying was the optimal drying method for maintaining high levels of bioactive compounds in 80% ethanol extracts of dried black chokeberries.     

The effect of addition of chokeberry, flowering quince fruits and rhubarb juice to strawberry jams on their polyphenol content, antioxidant activity and colour

The aim of the study was to establish whether the addition of berries (flowering quince, chokeberry) and rhubarb juice during jam processing improves its colour and enriches jams in polyphenol compounds other than those found in strawberries. The sum of phenolic compounds determined by HPLC was distributed in a wide concentration range depending on the cultivar. Jams prepared from Elkat cultivar had 27% more total phenolic compounds than jams prepared from Senga Sengana. The following compounds were identified in jams prepared from strawberries: p-coumaric, ferulic and ellagic acids, quercetin, kaempferol, anthocyanins, (+)-catechin, (−)-epicatechin and proanthocyanidins. Proanthocyanidins and ellagic acid are the major polyphenol compounds of all strawberries jams. The Elkat cultivar (47.34 mg/100 g) contained higher amounts of proanthocyanidins compared to Senga Sengana (29.95 mg/100 g). The addition of 10% of flowering quince and chokeberry to jams during their preparation resulted in the increase in the content of phenolic components in final products, especially for proanthocyanidins. The highest level of total polyphenols (P < 0.05) was found in strawberry mixed with chokeberry, 237.82 mg/100 g for Senga Sengana and 260.61 mg/100 g for Elkat. There has been a marked increase of proanthocyanidins content (5.4 and 4.0 times) in jams made from Senga Sengana and Elkat cultivars mixed with chokeberry. However, the addition of rhubarb juice did not increase the content of polyphenol in Senga Sengana jam (not statistically significant). Antioxidant activity of strawberry jam was determined by 2,2′azinobis-(3-ethylbenzthiazoline-6-sulphonic acid (ABTS), 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH) and ferric reducing/antioxidant power methods (FRAP). The antioxidant activity of this mixed jam was more than two times higher (P < 0.05) than control sample of strawberry jam. Rhubarb juice had high effect on L* (lightness) value in case of all strawberry varieties. The redness (a*), and yellowness (b*) were significantly different in jams with supplement. Strawberry jam with chokeberries had smaller L* value than control and other samples, and the lowest a* and b* values. This variation could be due to the nature of the pigments in these fruit cultivars and the content of anthocyanins which resulted in more reddish colour.     

Processing, Packaging, and Storage Effects on Quality of Freeze-Dried Strawberries

Water sorption isotherms of freeze-dried strawberries were determined using the interval sorption technique. The surface temperature during freeze-drying (from 20°C to 60°C) affected the hygroscopicity of the strawberries, particularly below 0.40 a_w. Over 1 yr, quality changes in dried strawberries were evaluated by sensory analysis at 3-month intervals. Crushing before drying and low processing temperatures improved sensory quality of dried strawberries and vacuum packaging improved storage stability.     

Rehydration and sorption properties of osmotically pretreated freeze-dried strawberries

The aim of this work was to investigate the influence of osmotic dehydration and type of osmotic solution on selected physical properties of freeze-dried strawberries. Frozen Senga Sengana strawberries were dehydrated in osmotic solution with water activity of about 0.9 (sucrose and glucose solutions and starch syrup). Osmotically dehydrated fruits were frozen and freeze-dried at heating shelf temperature of 30 °C for 24 h.     

The Effect of Microwave-Vacuum Pretreatment on the Drying Kinetics,Color and the Content of Bioactive Compounds in Osmo-Microwave-Vacuum Dried Cranberries (<Emphasis Type="Italic">Vaccinium macrocarpon</Emphasis>)

The aim of this study was to compare the effectiveness of microwave-vacuum pretreatment conducted at 100, 500 and 800 W on the drying kinetics of whole cranberries (Vaccinium macrocarpon) during hybrid osmotic and microwave-vacuum drying. Additionally, the effect of microwave-vacuum pretreatment and subsequent osmo-microwave-vacuum drying on selected quality indicators of dried cranberries, including phenolic content, antioxidant activity and color, was studied, and the quality of samples was compared with freeze dried, microwave-vacuum dried and osmo-microwave-vacuum dried samples. Irrespective of microwave power, the initial pretreatment accelerated mass transfer during osmotic dehydration of cranberries, and the Weibull model well fitted the experimental data. Final microwave-vacuum drying of cranberries was a two-stage process involving a relatively long phase with a constant drying rate, followed by a short period with a decreasing drying rate. Microwave-vacuum and osmo-microwave-vacuum drying resulted in similar retention of polyphenols and similar antioxidant activity, both of which were relatively higher than in freeze-dried cranberries. However, microwave-vacuum pretreatment at low microwave power (100 W) before dehydration also resulted in high retention of phenolic compounds, high antioxidant activity and attractive color, which were consistent with the high content of total anthocyanins and flavonoids. Microwave-vacuum, osmo-microwave-vacuum and osmo-microwave-vacuum drying combined with microwave-vacuum pretreatment at low microwave power (100 W) were the most suitable methods for the production of high-quality dried whole cranberries.     

Effect of osmotic dehydration on the drying kinetics and quality of cashew apple

The effect of different osmotic pretreatments on cashew apple drying kinetics and product quality were investigated. The osmotic pretreatment was carried out in an incubator at constant temperature and agitation. The drying process was conducted in a fixed bed dryer at different temperatures and constant air velocity. Experimental data were fitted successfully using the Page and the two‐term exponential models for dried fresh and pretreated fruit, respectively. It was found that drying rates of osmosed fruits decreased owing to the presence of infused solutes. Evaluation of the final product was performed by means of ascorbic acid content, water activity and sensorial test. The osmotic pretreated samples showed the highest vitamin C losses and the lowest water activity. The samples pretreated in sucrose solution had the highest acceptance.     

An evaluation of the retention of quality characteristics in fresh and freeze-dried alpine strawberries

Alpine strawberries (Fragaria vesca) are used in fruit juice, marmalade, or jam production and as a result have economical importance in food sector. The fresh alpine strawberries have a tendency to lose their quality in a few days as a result of high water loss and spoilage. In this paper, the results of a study on the effects of freeze drying process on the characteristics of the alpine strawberries, such as firmness, sugar content, pH, colour, weight loss, dissolved solids, anthocyanin and vitamin C content with reference to the fresh, are reported. Freeze‐drying indicated no difference in the characteristics of the alpine strawberries when compared with the fresh. It is found that a slight acid or base addition onto the rehydrated alpine strawberry juice preserved the stability of pigments and the colour. In addition, the rehydrated alpine strawberry juice exhibited an antimicrobial activity towards an important foodborne pathogen, Enterobacter faecium ATCC 6057.     

Effects of Ultrasound Assistance on Dehydration Processes and Bioactive Component Retention of Osmo‐Dried Sour Cherries

Despite having numerous health benefits, dried sour cherries have proven to be more acceptable to consumers when infused with sugar or other sweeteners to enhance their flavor, which, in turn, leads to serious anthocyanin losses. For this reason, a consideration was made for the application of ultrasound to accelerate solid gain and shorten drying time, thus favoring bioactive component retention. To determine the usefulness of ultrasound as a tool for sour cherry osmotic infusion enhancement, the effect of sonication time on dehydration effectiveness, as well as the stability of bioactive components during osmotic treatment and consecutive convective drying, was investigated. Fruits were osmo‐dehydrated using a 60% sucrose solution for 120 min (40 °C), during which, ultrasound of 25 kHz (0.4 W/cm²), was applied for 0, 30, 60, 90, and 120 min, after which, the fruits were convectively dried. In the range of the applied ultrasound energy no significant effect of sonication on mass transfer intensification was observed; moreover, longer acoustic treatment seemed to retard moisture removal during subsequent convective drying, which can be related to the breakdown of the parenchyma cell walls caused by the prolonged ultrasound (US) action. It was concluded that although US assistance could be considered neutral for bioactive component retention, excessive sonication time can lead to some anthocyanin deterioration. According to high‐performance liquid chromatography analysis, the particular anthocyanin alterations, both during dehydration and final drying, occurred in a similar way. Sonication time prolongation caused approximately 10% more bioactive compound deterioration, than earlier, shorter trials.     

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.     

百香果—苹果复合发酵型乳饮料工艺优化及抗氧化性研究

目的:制作一款新型百香果、苹果发酵乳饮料。方法:以百香果、苹果和纯牛奶为原料,以感官评价、蛋白质含量为指标,利用模糊数学评价法,考察苹果汁添加量、百香果汁添加量、蔗糖添加量、发酵时间、菌种接种量对百香果—苹果风味发酵乳感官品质的影响,并对发酵乳的抗氧化性及各项指标进行检测。结果:百香果—苹果风味发酵乳的最佳配方为纯牛奶82.59%,百香果汁2.35%,苹果汁8.00%,蔗糖7.00%,增稠剂0.06%,菌种0.002 06%,发酵时间6.50 h。此条件下,发酵乳的感官评分为8.99,蛋白质含量为3.12 g/100 g,其理化指标和卫生指标均符合相关国标要求。抗氧化性结果表明,百香果—苹果乳饮料发酵后对DPPH自由基和羟自由基的清除率均比发酵前有所提升,分别为77.7%,45.7%。结论:最佳配方下得到的发酵乳呈淡黄色,具有良好的组织状态,无乳清析出,不分层,具有百香果和苹果的清香和发酵乳特有风味,酸甜比例合适。     

A different perspective to study the effect of freeze, air, and osmotic drying on oil absorption during potato frying

ABSTRACT:  The objective of this article is to assess the effect of different dehydration pretreatments on oil absorption and illustrate how the different ways results can be reported may even drive to opposite conclusions. To do so, potato cylinders were blanched in hot water and dried until a moisture content of 62% (w.b.) by either freeze-drying, air drying, and osmotic drying with a sucrose solution or osmotic drying with a NaCl solution. Control (blanched) and dried potatoes were deep-fat fried at 170 °C for time periods between 1 and 5 min. Water removal and total oil uptake were determined and 2 oil fractions were distinguished: superficial oil and penetrated oil. Compared to the control, freeze dried samples increased oil uptake in 15.4% (d.b.) whereas air-dried samples reduced it in 11.2% (d.b.). Similarly, osmotic dehydrated samples showed a high reduction in oil uptake compared to the control (up to 27%[d.b.] when using a sucrose solution). However, this high decrease in oil absorption was attributed to the increase in solids content occurring during the osmotic dehydration process rather than a reduction in the amount of oil taken up. In fact, when the amount of oil absorbed per cylinder was determined, it was verified that oil uptake of osmotically dehydrated samples was even higher than the control, as opposed to what has been previously reported in the literature. These results highlight the importance of selecting an adequate basis to carry out comparisons properly.