Emerging Trends in Microwave Processing of Spices and Herbs

Today, spices are integral part of our food as they provide sensory attributes such as aroma, color, flavour and taste to food. Further their antimicrobial, antioxidant, pharmaceutical and nutritional properties are also well known. Since spices are seasonal so their availability can be extended year round by adopting different preservation techniques. Drying and extraction are most important methods for preservation and value addition to spices. There are different techniques for drying of spices with their own advantages and limitations. A novel, non-conventional technique for drying of spices is use of microwave radiation. This technique proved to be very rapid, and also provide a good quality product. Similarly, there are a number of non-conventional extraction methods in use that are all, in principle, solid–liquid extractions but which introduce some form of additional energy to the process in order to facilitate the transfer of analytes from sample to solvent. This paper reviews latest advances in the use of microwave energy for drying of spices and herbs. Also, the review describes the potential application of microwave energy for extraction of essential oil/bioactive components from spices and herbs and the advantages of microwave-assisted process over the other extraction processes generally employed for extraction. It also showcases some recent research results on microwave drying/extraction from spices and herbs.     

Suitability of Different Food Grade Materials for the Encapsulation of Some Functional Foods Well Reported for Their Advantages and Susceptibility

Functional foods find a very important place in the modern era, where different types of cancer, diabetes, cardiovascular diseases, etc. are on a high. Irrespective of the abundance of bioactive components in different fruits and vegetables, their low solubility in aqueous solution, vulnerability to destruction in different environmental and gastrointestinal conditions and a low intestinal absorption becomes a concern. Because it is quite difficult to commercialize non food materials for the food encapsulation purposes due to their safety concerns in the human body, scientists in the recent times have come up with the idea of encapsulating the different bioactive components in different food grade materials that are able to safeguard these bioactive components against the different environmental and gastrointestinal conditions and ensure their safe and targeted delivery at their absorption sites. Different food grade encapsulation materials including various oligosaccharides, polysaccharides (starch, cyclodextrins, alginates, chitosan, gum arabic, and carboxymethyl cellulose) and proteins and their suitability for encapsulating various bioactive components like flavonoids (catechins, rutin, curcumin, hesperetin, and vanillin), nonflavonoids (resveratrol), carotenoids (β-carotene, lycopene, and lutein), and fatty acids (fish oil, flaxseed oil, and olive oil) of high medical and nutritional value are reviewed here.     

鱼类血红蛋白诱导脂质氧化及其控制的研究进展

脂质氧化不仅使食品的营养、风味、质构和外观发生变化,而且缩短了产品的货架期,降低其食用品质,是造成水产食品品质劣变的重要原因之一。血红蛋白是水产品脂质氧化的重要诱导因子,其自动氧化产生的高铁血红蛋白可以加速脂质氧化反应速率,同时释放的血红素和铁离子也可催化脂质氧化的发生。化学防腐剂在食品中的应用越来越受到限制,天然抗氧化剂的研究与应用已成为热点,了解血红蛋白促氧化的机理,找到适宜的抗氧化技术,有效地控制水产品在贮藏过程中血红蛋白诱导的脂质氧化的发生是非常必要的。因此,本文以血红蛋白诱导的脂质氧化为切入点,介绍了鱼类血红蛋白的结构、促氧化的反应机理和影响因素,以及天然酚类抗氧化物在控制血红蛋白促氧化方面的诸多应用与进展,并提出了目前急需解决的问题和未来的研究趋势。     

Antioxidant and Anti-diabetic Properties of Caryota Urens (Kithul) Flour

Starch extracted from pith of Caryota urens L. (Family: Arecaceae) palm is known as “Kithul flour” and is claimed to have health benefits according to folklore and Ayurveda. Antioxidants are believed to possess numerous health benefits. However, as yet, health benefits of C. urens flour have not been scientifically investigated. Antioxidant properties of C. urens flour were tested using different in vitro assays namely, 2,2-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS⁺), ferric reducing antioxidant power, oxygen radical absorbance capacity and ferrous ion chelating assays. Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) were also evaluated. Anti-diabetic properties were estimated using alpha amylase and alpha glucosidase enzyme inhibition assays. Dried methanolic extracts of both boiled and raw samples were used in all assays. Results of the study showed that C. urens flour possess free radical scavenging activity(raw 0.02± 0.01 and boiled 0.04±0.01 mg trolox equivalent (TE)/ g flour), electron donating reducing power (raw 0.10±0.03 and boiled 0.36±0.11 mg TE/g flour), oxygen radical absorbance capacity (raw 2.29± 0.71 and boiled 192.3 ± 57.71 mg TE/1 g flour) and metal ion chelating capacity (raw 0.03±0.01 and boiled 0.14±0.04 mg EDTA equivalents /g flour) exhibiting its antioxidant potential. TPC (raw 1.1±0.3 and boiled 5.12 ± 1.89 mg GAE/g flour) and TFC (raw 1.65 ± 0.47 and boiled 6.69 ± 1.27 μg QE/g flour) which are said to be contributed to antioxidant activities were also found. In addition, boiled flour which is generally consumed as a food has shown higher antioxidant activity. Caryota urens flour did not contain marked anti-diabetic properties. It is evident from results that Caryota urens flour has moderate antioxidant property which may associate with its traditional health claims.     

压力差示扫描量热法在润滑油热氧化研究中的应用

介绍了用压力差示扫描量热法评定基础油、抗氧剂和润滑油抗氧化性能的方法。PDSC扫描量热法与发动机台架试验有一定的对应关系,可以评价发动机油的抗氧化性能。     

Synthesis and aging properties of reactive antioxidant NAPM in natural rubber vulcanizates

The rubber antioxidant N‐(4‐anilinophenyl) methacrylamide (NAPM) was synthesized by a two‐step reaction using thionyl chloride (SOCl₂) with methacrylic acid (MAA) and consequently 4‐aminodiphenylamine (ADPA) as precursors. NAPM was characterized by IR, ¹H NMR and elemental analysis. Thermal stability, aging property of NAPM and mechanical properties of natural rubber (NR) vulcanizates containing NAPM were investigated and compared with two other commercial antioxidants N‐isopropyl‐N′‐phenyl‐p‐phenylene diamide (4010NA) and N‐(1, 3‐dimethyl butyl)—N′‐phenyl‐p‐phenylene diamide (4020). It was found that NAPM was an effective antioxidant with a better thermal stability and higher antiaging resistance than unreactive antioxidants 4010NA and 4020. And unsaturation level of NR vulcanizates containing NAPM was lower than that of 4010NA and 4020. Moreover, an antiaging resistant mechanism of a surface reaction between NAPM and cis‐1, 4‐polyisoprene in NR was proposed to explain the better properties of NAPM based on the IR and SEM analyses. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Analysis of the Influence of Processing Conditions on the Supramolecular Structure and Antioxidant Distribution in PP‐Pipes Using Infrared Microscopy

The supramolecular structure in pipe walls of isotactic PP‐R is a function of compound composition and processing parameters, which both influence the mechanical properties of the pipes. µFTIR shows a gradient of the crystallinity across the pipe wall, with a lower‐crystalline outer layer, and a higher‐crystalline core layer. The rate of extrusion has an influence on the thickness of the outer layer. The nucleating effect on the morphological profile throughout the pipe wall can be visualised. µFTIR shows a homogeneous distribution of the primary antioxidant in the pipe wall. Both the spectral crystallinity and the antioxidant concentration distribution are calculated.

     

抗氧化剂168的高效液相色谱法分析

探讨了抗氧化剂168的高效液相色谱分析方法,采用甲醇/乙酸乙酯作流动相。实验表明,在0.2～0.8 mg/mL具有较好的线性,平行测定5组数据,其标准偏差为0.011,质量回收率99.7%～102.7%。