Comparison of enzyme‐assisted and ultrasound‐assisted extraction of vitamin C and phenolic compounds from acerola (Malpighia emarginata DC.) fruit

This article describes a comparative study of enzyme and ultrasound techniques for the simultaneous extraction of vitamin C and phenolic compounds from acerola fruit. Ultrasound‐assisted extraction (UAE) took only 6 min to achieve the highest level of vitamin C and phenolic compounds as well as antioxidant activity of acerola juice, while enzyme‐assisted extraction (EAE) took up to 120 min to obtain the maximal values. On the basis of kinetic model of second‐order extraction, the extraction rate constant of vitamin C and phenolics in UAE increased approximately 3.1 and 2.7 times, respectively, in comparison with that in EAE. In addition, the maximal level of vitamin C, phenolics and the antioxidant activity evaluated by 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), and 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) methods in UAE was 4.6%, 3.5%, 4.6% and 3.3%, respectively, higher than those in EAE. Obviously, UAE is a useful method for the extraction of antioxidants from plant materials.     

Effect of pulsed ultrasound treatment compared to continuous mode on microbiological and quality of Mirabelle plum during postharvest storage

The effects of pulsed and continuous ultrasound treatment on microbiological and physiological quality of Mirabelle plum fruit were investigated. Freshly harvested Mirabelle plum was treated with 30‐kHz pulsed and continuous ultrasound at 20 °C for 0, 15, 30, 45 and 60 min and subsequently stored at 4 °C for 10 days. The total count of bacteria, total fungi, decay index, titratable acidity (TA), total soluble solids (TSS), colour, texture, ascorbic acid content and total phenolics was measured. The results showed that pulsed and continuous ultrasonic treatment significantly (P < 0.05) reduced the number of microorganisms and improved the quality of Mirabelle plums during storage. Increasing pretreatment time enhanced the positive effects of pulsed and continuous ultrasound. Also, in terms of the total count of bacteria, total fungi, titratable acidity and total phenolics, the pulsed and continuous ultrasound did not show a significant difference (P < 0.05). However, pulsed ultrasound was better compared to continuous mode in preservation of TSS, colour, texture and ascorbic acid content of the fruit during storage. Our results demonstrated that pulsed ultrasound is an appropriate method for improving safety and maintaining the quality of Mirabelle plum fruit.     

The efficiency and comparison of novel techniques for cell wall disruption in astaxanthin extraction from Haematococcus pluvialis

The efficiency of various techniques pulsed electric field (PEF), ultrasound (US), high‐pressure microfluidisation (HPMF), hydrochloric acid (HCl) and ionic liquids (ILs) for cell wall disruption in astaxanthin extraction from Haematococcus pluvialis was compared. The results indicated that ILs, HCl and HPMF treatment were shown the most efficient for cell disruption with more than 80% astaxanthin recovery. While the cell wall integrity of H. pluvialis cyst cell was less affected by US and PEF treatment. It was found that imidazolium‐based ILs showed the greater potential for cell disruption than pyridinium‐based and ammonium‐based ILs. Among all the ILs examined, 1‐butyl‐3‐methylimidazolium chloride ([Bmim] Cl) exhibited efficient cell disruption and capability of astaxanthin recovery at mild condition (pretreatment with 40% IL aqueous solution at 40 °C, followed by extraction with methanol at 50 °C) without extensive energy consumption and special facility requirement. In addition, recyclability of ILs was excellent.     

香菇多酚超声波提取工艺及抗氧化性分析

以干香菇为原料,乙醇溶液作为提取溶剂,在单因素试验的基础上,结合响应面法优化了香菇多酚的提取工艺,并采用大孔树脂吸附法对香菇多酚进行分离纯化,通过体外试验来评价其抗氧化活性.试验结果表明,香菇多酚的最佳工艺参数为乙醇浓度50％、提取温度74℃、料液比1∶42 (g/mL)、超声功率146 W,在此条件下,香菇多酚得率为...     

Optimisation and modelling green bean's ultrasound blanching

Using of ultrasound in food processing is a novel and interesting technique, which is often complementary to classical methods. This study reports on the ultrasound blanching (USB) of green bean. Response surface methodology (RSM) was used to study the effect of process variables on the USB. Three independent variables including temperature (50–90 °C), time (45–225 s) and duty cycle (0.2–0.8 s) were examined. The optimal USB conditions were obtained with a temperature of 90 °C, USB time of 58.27 s and duty cycle of 0.79 s. At these conditions, the residual peroxidase activity (RPA) determined as 9.64% and the vitamin C loss as 8.92%. The experimental values under optimal condition were in good consistent with the predicted values. According to the results, the USB process is more efficient process and as well as less damage to the product compared to the conventional blanching method.     

超声辅助酶解大米多肽的制备及其对酵母细胞增殖性影响

采用超声辅助酶解制备大米多肽,并研究其对酵母细胞增殖性的影响。在单因素试验基础上,对超声辅助酶解制备大米多肽进行工艺优化,确定最优超声辅助酶解工艺:超声功率密度51.8 W/L、超声温度50℃、超声时间15 min。在最优工艺条件下,大米多肽得率为70.57%。对酵母细胞培养增殖显示随着多肽浓度的增加而增强,当多肽浓度达到25 g/L后,酵母细胞增殖效果不再增强;另外超声辅助酶解的大米蛋白多肽作为氮源对酵母细胞培养增殖效果要好于常规酶解。     

Scanning the future--ultrasonography as a reproductive management tool for dairy cattle

Application of transrectal real-time ultrasonography as a research tool to study bovine reproduction represents a technological breakthrough that has revolutionized our understanding of reproductive biology in cattle. The widespread adoption and use of ultrasonography for routine reproductive examinations of dairy cattle by bovine practitioners is the next contribution this technology will make to the dairy industry. Assessment of pregnancy status and fetal viability early postbreeding to identify cows that fail to conceive improves reproductive efficiency by decreasing the interval between artificial insemination services and increasing artificial insemination service rate. Early identification of cows carrying twin fetuses will allow for implementation of differential management strategies to abrogate negative effects of twinning during the periparturient period once such strategies have been developed. Ovarian and uterine pathologies not accurately detected via rectal palpation can easily be visualized by ultrasound, and appropriate therapies can be implemented. Determination of fetal sex in utero is useful when coupled with a management decision that justifies the expense of fetal sexing. Development of integrated reproductive management systems that combine ultrasound with new and existing reproductive technologies will further enhance the practical applications of ultrasonography. Development of Extension education programs to train bovine practitioners to use ultrasound for routine reproductive examinations is a critical step toward rapid implementation of this technology into the dairy industry.     

超声强化亚临界CO_2萃取小球藻中叶黄素的研究

采用超声强化亚临界CO2技术研究了从小球藻中萃取叶黄素的工艺条件,并初步分析了超声强化的机理。实验中考察了萃取温度、萃取压力、流体流量、夹带剂用量、萃取时间及超声功率对叶黄素萃取率的影响,得到了最佳的工艺条件:萃取温度25℃,萃取压力11MPa,流体流量30kg/h,夹带剂用量为1.5mL/g的无水乙醇,萃取时间3h,超声功率750W。     

Influence of ethanol/water ratio in ultrasound and high‐pressure/high‐temperature phenolic compound extraction from agri‐food waste

The valorisation and management of agri‐food waste are currently hot investigation topics which probe the recovery of valuable compounds, such as polyphenols. In this study, high‐pressure/high‐temperature extraction (HPTE) and ultrasound‐assisted extraction (UAE) have been used to study the recovery of phenolic compounds from grape marc and olive pomace in hydroalcoholic solutions. The main phenolic compounds in both extracts were identified by HPLC‐DAD. Besides extraction yield (total polyphenol and flavonoid content) and the antiradical power, polyphenol degradation under HPTE and UAE has also been studied. HPTE with ethanol 75% gave higher phenolic extraction yields: 73.8 ± 1.4 mg of gallic acid equivalents per gram of dried matter and 60.0 mg of caffeic acid equivalents per gram of dried matter for grape marc and olive pomace, respectively. In this study, the efficient combination of ethanol/water mixture with HPTE or UAE has been used to enhance the recovery of phenolic compounds from grape marc and olive pomace. HPLC‐DAD showed that UAE prevents phenolic species degradation damage because of its milder operative conditions.     

Effect of high power ultrasonic treatment on whey protein foaming quality

High power ultrasonic energy at 20%, 40% and 60% amplitude was applied on whey protein suspension at concentrations of 100, 150 and 200 g kg^?1 for 5, 15 and 25 min to improve its foaming quality. Ultrasound‐treated whey protein suspension at 200 g kg^?1 showed improvement in terms of increased foaming capacity by 18%, foam stability by 35%, consistency index by 18%, storage modulus by 17%, loss modulus by 26% and viscosity by 21% compared with untreated whey protein. For maximally ultrasound‐treated samples of 60% amplitude treated for 25 min, the improved whey protein foams also had a 46% increase in the number of more evenly distributed fine bubbles which had a size smaller than 0.0025 mm³ as imaged using X‐ray microtomography.