Distilled beverage aging: A review on aroma characteristics,maturation mechanisms,and artificial aging techniques

The market value of distilled beverage relies on its quality with a major contribution of distinctive and fascinating aromas. The aroma of distilled beverage is built on the basis of chemical components and can be modified through a series of physical and chemical processes such as aging. Revealing the hidden knowledge behind the evolution of numerous chemical components during these physicochemical processes in distilled beverages is not only significant but also challenging due to its complex system. In this review, the trends in the changes of associated aroma compounds over aging are proposed on the basis of understanding the relationship between chemical components and aroma profiles of numerous typical distilled beverages. The different aging systems, both classical platforms from Eastern countries (pottery jars) to Western countries (wood barrels), and modern platforms such as artificial aging technologies are outlined and compared with their respective applications. Optimizing aging processes is a challenging but imperative step, which warrants further fundamental knowledge from targeting aging-related molecules to the exploration of multitude physicochemical reaction mechanisms that occur during this process, such as the formation of potent odorant compounds in specific containers and environments, as well as mass transfer processes between solid and liquid interfaces. Understanding these maturation mechanisms of distilled beverages expressed by chemosensory signature holds promise for major improvements in future aging technologies that can efficiently yield stable and high-quality products.     

Coupled partitioning, dilution, and chemical aging of semivolatile organics

A unified framework of semi-volatile partitioning permits models to efficiently treat both semi-volatile primary emissions and secondary organic aerosol production (SOA), and then to treat the chemical evolution (aging) of the aggregate distribution of semi-volatile material. This framework also reveals critical deficiencies in current emissions and SOA formation measurements. The key feature of this treatment is a uniform basis set of saturation vapor pressures spanning the range of ambient organic saturation concentrations, from effectively nonvolatile material at 0.01 microg m(-3) to vapor-phase effluents at 100 mg m(-3). Chemical evolution can be treated by a transformation matrix coupling the various basis vectors. Using this framework, we show that semi-volatile partitioning can be described in a self-consistent way, with realistic behavior with respect to temperature and varying organic aerosol loading. The time evolution strongly suggests that neglected oxidation of numerous "intermediate volatility" vapors (IVOCs, with saturation concentrations above approximately 1 mg m(-3)) may contribute significantly to ambient SOA formation.     

Diet,the intestinal microbiota,and immune health in aging

Many countries are facing aging populations, with those over 65 years of age likely to represent the largest population over the next 10–20 years. Living longer often comes with poor health and, in particular, a decline in the immune function characterized by poor vaccine responses and increased risk of infection and certain cancers. Aging and diet represent major intrinsic and extrinsic factors that influence the makeup and activity of resident intestinal microbes, the microbiota, the efficient functioning of which is essential for sustaining overall health and the effectiveness of the immune system. The provision of elderly specific dietary recommendations appears to be lacking but is necessary since this population has an altered microbiota and immune response and may not respond in the same way as their healthy and younger counterparts. We have reviewed the evidence supporting the role of diet and, in particular, dietary carbohydrate, protein, and fat in influencing the microbiota and its generation of key metabolites that influence the efficient functioning of immune cells during aging, and how dietary intervention might be of benefit in improving the intestinal health and immune status in the elderly.     

Acetylated,isocyanate-bonded flakeboards after accelerated aging

To improve flakeboard dimensional stability and mechanical properties for long-term exterior exposure, we fabricated and tested a highly durable isocyanate-bonded acetylated flakeboard. Flakeboards were tested for internal bond strength, thickness swell, modulus of elasticity, modulus of rupture, and breaking strength in bending, after two severe accelerated aging tests. Flake design, flakeboard density, resin content, and their interactions were critical to the performance of acetylated flakeboards in the aging tests. In bending tests, the longer disc-cut flakes produced much higher strength values than did the ring-cut flakes. In internal bond strength tests, the ring-cut flakes performed comparably to the disc-cut flakes. However, ring-cut flakes contributed somewhat more to reducing thickness swell than did disc-cut flakes. Acetylated flakeboards fabricated at high density were much stronger than those fabricated at low density. However, the high-density boards developed more thickness swell than did the low-density boards. The 5-% resin content contributed little to increased strength values in the bending tests, but this level of resin significantly improved flakeboard performance internal bond strength and thickness swell tests. Acetylation did not interfere to any practical degree with the isocyanate resin, and all property values were enhanced by acetylation, particularly internal bond strength and resistance to thickness swell.     

Hygrothermal aging properties,molding and abrasion resistance of bamboo keyboard

Bamboo keyboards made from bamboo panels are exposed to the influence of mold infection, hygrothermal environment and repeated wear. Mold resistance and hygrothermal aging properties of bamboo keyboard under different treatments were investigated. The abrasion resistance was experimentally studied and compared between bamboo keyboard and plastic keyboard. The results indicated that the bamboo keyboard treated with H₂O₂ exhibited the best mold resistance, followed by that treated with varnish, and then came the ones with mildew preventive treatment and the control specimens. Although hardly visible to the naked eye after 4 weeks of mold infection test, mold was observed on most plastic keyboards through microscopic examination. For aging test, the shrinkage ratio of bamboo keystroke was 0.34, 0.46 and 0.62 % after high and low temperature (HLT) treatment, while the swelling ratio was 0.01, 1.14 and 1.93 % after constant temperature and humidity (CTH) treatment, respectively. Similar trend in the ratio of dimensional change was observed in terms of both drying shrinkage and hydroscopic swelling: thickness direction > perpendicular-to-grain direction > grain direction. By manual observation, the bamboo keyboard had an advantage over plastic keyboards in terms of the adaptability to an environment of changing temperature. For abrasion test, the wear point of bamboo keyboard was 650 r and that of plastic 150 r indicating that bamboo keyboards performed better in terms of abrasion resistance than plastic ones.     

Effects of dry aging of bone-in and boneless strip loins using two aging processes for two aging times

This experiment investigated the combined effects of two dry-aging methods (unpackaged and in a bag), two loin-cut styles (bone-in shell loins and boneless strip loins), and two aging times (21 and 28 days) on the physical, chemical, sensory, and microbial properties of dry-aged beef. Sections from shell and strip loin were assigned randomly to be aged unpackaged or aged packaged in a bag with high moisture permeability. Weight losses increased with aging time. Shell loins lost more (P < 0.05) weight during aging compared with strip loins; dry aging in a bag had less (P < 0.05) weight loss than unpackaged aging. There were no differences (P > 0.05) in any of the sensory traits between shell and strip loins or dry aging using a traditional method or in a bag. Dry aging in a bag creates positive effects on yields, no negative effects on product quality, and adds flexibility and control of the aging environment.     

Effects of dry aging of bone-in and boneless strip loins using two aging processes for two aging times

This experiment investigated the combined effects of two dry-aging methods (unpackaged and in a bag), two loin-cut styles (bone-in shell loins and boneless strip loins), and two aging times (21 and 28 days) on the physical, chemical, sensory, and microbial properties of dry-aged beef. Sections from shell and strip loin were assigned randomly to be aged unpackaged or aged packaged in a bag with high moisture permeability. Weight losses increased with aging time. Shell loins lost more (P < 0.05) weight during aging compared with strip loins; dry aging in a bag had less (P < 0.05) weight loss than unpackaged aging. There were no differences (P > 0.05) in any of the sensory traits between shell and strip loins or dry aging using a traditional method or in a bag. Dry aging in a bag creates positive effects on yields, no negative effects on product quality, and adds flexibility and control of the aging environment.     

The effect of aging on low-fat, reduced-fat, and full-fat Cheddar cheese texture

This study investigated the effects of aging and fat content on the texture of Cheddar cheese, both mechanical and sensory aspects, over a 9-mo aging period. Cheeses of 6, 16, and 33% fat were tested at 0.5, 3, 6, and 9 mo of aging. Cheeses were evaluated by a trained sensory panel using an established texture lexicon as well as instrumental methods, which were used to probe cheese structure. Sensory analysis showed that low-fat cheeses were differentiated from full-fat cheeses by being more springy and firm and this difference widened as the cheeses aged. In addition, full-fat cheeses broke down more during chewing than the lower fat cheeses and the degree of breakdown increased with aging. Mechanical properties were divided by magnitude of deformation during the test and separated into 3 ranges: the linear viscoelastic region, the nonlinear region, and fracture point. These regions represent a stress/strain response from low to high magnitude, respectively. Strong relationships between sensory terms and rheological properties determined in the linear (maximum compliance) and nonlinear (critical stress and strain and a nonlinear shape factor) regions were revealed. Some correlations were seen with fracture values, but these were not as high as terms related to the nonlinear region of the cheeses. The correlations pointed to strain-weakening behavior being the critical mechanical property. This was associated with higher fat content cheeses breaking down more as strain increased up to fracture. Increased strain weakening associated with an increase in fat content was attributed to fat producing weak points in the protein network, which became initiation sites for fracture within the structure. This suggests that fat replacers need to serve this functional role.     

Ozone-initiated particle formation, particle aging, and precursors in a laser printer

An increasing number of researchers have hypothesized that ozone may be involved in the particle formation processes that occur during printing, however no studies have investigated this further. In the current study, this hypothesis was tested in a chamber study by adding supplemental ozone to the chamber after a print job without measurable ozone emissions. Subsequent particle number concentration and size distribution measurements showed that new particles were formed minutes after the addition of ozone. The results demonstrated that ozone did react with printer-generated volatile organic compounds (VOCs) to form secondary organic aerosols (SOAs). The hypothesis was further confirmed by the observation of correlations among VOCs, ozone, and particles concentrations during a print job with measurable ozone emissions. The potential particle precursors were identified by a number of furnace tests, which suggested that squalene and styrene were the most likely SOA precursors with respect to ozone. Overall, this study significantly improved scientific understanding of the formation mechanisms of printer-generated particles, and highlighted the possible SOA formation potential of unsaturated nonterpene organic compounds by ozone-initiated reactions in the indoor environment.     

Connective tissue and aging

Human skin is composed of epidermal and dermal layers, each of which has its own functional importance. Dermis consist of a fine network of collagen fibers, elastic fibers, and other components of the extracellular matrix (ECM). ECM consist primarily of proteins and complex sugars, which form fibrillar networks and a ground substance. Collagen is an important structural component of skin connective tissue and provides the tensile strength of skin. Approximately 70–80% of the dry weight of skin consists of collagen. The most abundant collagen types in skin are types I and III; the former accounts for 80% of the total collagen content of skin and the latter for approximately 15%. The other collagen types present in skin include type IV collagen, which is abundant in the basement membrane (BM); type V collagen, which is located pericellularly; type VI collagen, which plays a role in matrix assembly and is present as microfibrils between collagen fibers; and type VII collagen, which is a structural component of anchoring fibrils. Elastin accounts for only about 1–2% of the dry weight of skin but is important for the maintenance of skin elasticity and resilience. Glycosaminoglycans are of central importance for the maintenance of a water balance in skin, even though the quantities in ECM are small (0.1–0.3% of the dry weight of skin). In the dermis fibroblasts are responsible for the synthesis of ECM proteins. The fibroblasts in the dermis spend majority of time in quiescent state. However in response to activation, the fibroblasts can be reactivated, and certain pool of cell is able to differentiate into myofibroblasts which have important role in repairing skin defects such as during wound healing. During aging the number of fibroblasts is markedly reduced. Also the response of fibroblasts to various growth factors and mechanical or pathological stimulates (wound healing) is diminished. Skin collagen synthesis declines with aging and as the result of such external factors as long‐term sun exposure and medications, for example, topical corticosteroids. In aging skin, collagen fibers become thicker and less soluble and the synthesis of collagen declines. Skin thickness remains quite constant between 20 and 70 years of age, after which a marked decrease in skin thickness occurs. During aging the expression of collagenases are increased and inhibitors of collagenases are reduced leading to increased proteolysis of connective tissue. Recent studies have shown that collagen synthesis is declined in the skin of heavy smokers, while collagenases are increased inducing premature skin aging. The elastic properties of skin are also affected by aging. Along with increasing age, dermal elastic fibers become thicker and fragmented and oxytalan fibers appear fragmented and shortened. Disintegration of elastic fibers is already seen in a minority of fibers between ages 30 and 70, but the changes become more profound after the age of 70 years, affecting a majority of the fibers. As a result of the decreased number of elastic fibers in aged skin, the elastic recovery of skin decreases in elderly people. Even though the content of GAGs and proteoglycans is relatively small, they have significant role in collagen fibril formation, water content of dermis and in mechanical properties. During aging there are marked alterations in different proteoglycans. The amount and synthesis of versican (high molecular size) is decreased and small molecular size decorin is increased. In photoaged skin versican is increased and is closely associated to elastin while decorin is decreased.     

两种光老化设备QUV紫外荧光老化试验箱和Q-Sun氙灯老化试验箱比较

紫外荧光老化试验箱QUV采用荧光紫外灯为光源,通过模拟自然阳光中的紫外辐射和冷凝,对材料进行加速耐候性试验,以获得材料耐候性的结果。氙灯老化试验箱Q-Sun采用能模拟全阳光光谱的氙弧灯来再现不同环境下存在的破坏性光波,用来进行老化的环境模拟和加速试验。QUV和Q-Sun同属加速老化和测试材料光稳定性的设备,能提供快速且可重复的测试结果。本文论述了这两种仪器的特点和相关主要标准,并比较了两者之间差别。     

枣酒和其他果酒澄清净化及陈化技术研究进展

澄清净化处理可以保证果酒的品质并保持最佳感官品评效果和稳定性。陈化技术能够加速果酒的陈酿时间,降低企业生产成本,提高经济效益。该文主要概述了枣酒及其他果酒的澄清净化的方法及陈化技术的研究现状,并对黑化红枣酒的研究现状、澄清净化及人工催陈技术进行总结,以期为枣酒及其他果酒的产业化开发提供一定参考。     

Effects of blade tenderization,aging method and aging time on meat quality characteristics of Longissimus lumborum steaks from cull Holstein cows

The effects of blade tenderization (BT), two aging methods (dry (D) and wet (W)), and aging time (2 and 23 d) on tenderness, color, and sensory properties of Longissimus lumborum muscles from 12 cull Holstein cows were evaluated. Dry-aged loins had higher combined trim and aging losses than control (C) for both D- and W-aging, mostly because of excess trim losses. BT steaks had WBSF of 33.13 N while C steaks had WBSF of 41.46 N (P = 0.09). Aging decreased WBSF. Blade tenderized steaks had higher cook loss than C steaks. Aging, W-aging, and BT × W-aging improved myofibrillar (sensory) tenderness scores. Aging and/or BT improves sensory panel tenderness cull cow Longissimus lumborum steaks. Aging and blade tenderization combined can increase tenderness and value of Longissimus steaks from cull Holstein cows.     

优化橡木桶陈酿工艺在干红葡萄酒生产中的应用

通过研究陈酿过程中橡木桶陈酿酒所占比例、烘烤程度及陈酿时间三种不同因子对葡萄酒品质的影响,找出其不同水平组合对葡萄酒品质影响的重要性,确定葡萄酒品质最好的水平组合,作为干红葡萄酒的最适陈酿方案。     

Topical niacinamide reduces yellowing, wrinkling, red blotchiness, and hyperpigmented spots in aging facial skin

Previous clinical testing of topical niacinamide (vitamin B3) has revealed a broad array of improvements in the appearance of aging facial skin. The study reported here was done to confirm some of those previous observations and to evaluate additional end points such as skin anti-yellowing. Caucasian female subjects (n = 50, aged 40-60 years) participated in a 12-week, double-blind, placebo-controlled, split-face, left-right randomized clinical study assessing two topical products: moisturizer control product versus the same moisturizer product containing 5% niacinamide. Niacinamide was well tolerated by the skin and provided significant improvements versus control in end points evaluated previously: fine lines/wrinkles, hyperpigmentation spots, texture, and red blotchiness. In addition, skin yellowing (sallowness) versus control was significantly improved. The mechanism by which this array of benefits is achieved with niacinamide is discussed.     

Effect of HPMC addition on the microstructure, quality and aging of wheat bread

The effect of hydroxypropylmethylcellulose (HPMC) addition on a basic bread formulation is described. The effect of HPMC as bread improver and antistaling agent was analysed in terms of microstructure. Bread quality was assessed by physical parameters (volume, width/height ratio, moisture content and hardness), crumb grain structure (number of air cells, cells area and the ratio between cells area and total area) and sensory evaluation (appearance, aroma, taste and texture). Bread staling was determined by following both the hardness increase and the starch retrogradation during storage. The microstructure was analyzed by cryo scanning electron microscopy (cryo-SEM). The results confirm the ability of the HPMC for improving fresh bread quality and for delaying staling. The presence of HPMC decreased the hardening rate of the bread crumb and also retarded the amylopectin retrogradation. The microstructure analysis revealed the possible interaction between the HPMC and the bread constituents, which could partially explain the antistaling effect of this hydrocolloid.     

小麦新陈的鉴别

比较小麦新陈鉴别的几种方法。用高锰酸钾滴定法测定过氧化氢酶活动度,可以定量对小麦的新陈进行较准确鉴别。探讨影响此方法的诸多因素以及在测定中对pH值、时间、温度等影响因素的控制条件,力求得到准确的测定结果。