黑曜岩资源化利用研究现状与展望

黑曜岩是类似于珍珠岩的一类火山喷发冷凝岩石,其应用远古即有,它的利用价值目前主要集中在考古及建材生产方面。根据矿物组分开发新的资源利用途径和高附加值产品,是黑曜石资源化利用的研究重点。     

云南甘蔗有性杂交育种亲本的使用及效益分析

本文根据40年来云南甘蔗有性杂交育种的资料，从亲本类型，利用方式，重要组合及血缘系统等方面分析了甘蔗品种选育的效益，探讨了提高甘蔗育种效益的可能途径。     

盐碱联合循环中制碱废液资源化利用的研究

从理论分析入手,对盐碱联合循环工艺过程中产生的氨碱废液进行了较全面地研究,结合淮安井矿生产实际．提出了氨碱废液资源化综合利用的几个途径。     

富含不饱和脂肪酸食品加工过程中的组分变化研究与展望

对食品中不饱和脂肪酸的来源、功效及其在加工过程中组分变化作概述.详细介绍了食品加工过程中不饱和脂肪酸的自动氧化、光氧化和酶促氧化过程;分析热加工过程中不饱和脂肪酸氧化机理,探讨辐照对食品中脂肪酸裂解的影响.在此基础上,总结了富含不饱和脂肪酸食品在加工过程中存在的典型问题,并分析相关的科学研究瓶颈,展望富含不饱和脂肪酸食品加工的发展趋势,期望对相关领域的科学研究有所启发.     

β-carotene content in sweet potato varieties from China and the effect of preparation on β-carotene retention in the Yanshu No. 5

To compare the β-carotene contents in different Chinese sweet potato (SP) varieties and to choose a variety of SP rich in β-carotene for the study of the effect of processing methods on β-carotene retention, β-carotene in thirteen varieties of sweet potato from China was measured by HPLC. The results showed that β-carotene contents were significantly correlated with SP flesh colours, with the orange-red fleshed SP varieties being higher in β-carotene.β-carotene contents in SP were affected by many factors, and this was demonstrated using the variety of Yanshu No.5, showing that the β-carotene contents in SP grown in different farming sites in the same area ranged from 53.2 to 84.3 mg kg^− 1 fresh weight. Moreover, β-carotene distributes unevenly in one SP root, with highest concentrations in the core. The β-carotene content was positively related to the root size.Five processing methods including boiling, steaming, microwave cooking, frying, and post steam-drying were simulated in the study to check their effects on the true retention of β-carotene in SP. Compared to boiling, steaming resulted in much more loss of β-carotene and microwave cooking resulted in the biggest loss of β-carotene among the five processing methods.

Industrial relevance

Orange-fleshed sweet potato can be prepared for sale and consumption, using methods that protect the β-carotene content. This can aid in promoting sweet potato as a staple food as well as a snack food for supplying vitamin A for both rural and urban populations. Prepared orange-fleshed sweet potato can contribute to alleviating vitamin A deficiency in China as well as other low-income countries.     

Influence of unit operations on the levels of polyacetylenes in minimally processed carrots and parsnips: An industrial trial

Carrots and parsnips are often consumed as minimally processed ready-to-eat convenient foods and contain in minor quantities, bioactive aliphatic C17-polyacetylenes (falcarinol, falcarindiol, falcarindiol-3-acetate). Their retention during minimal processing in an industrial trial was evaluated. Carrot and parsnips were prepared in four different forms (disc cutting, baton cutting, cubing and shredding) and samples were taken in every point of their processing line. The unit operations were: peeling, cutting and washing with chlorinated water and also retention during 7 days storage was evaluated. The results showed that the initial unit operations (mainly peeling) influence the polyacetylene retention. This was attributed to the high polyacetylene content of their peels. In most cases, when washing was performed after cutting, less retention was observed possibly due to leakage during tissue damage occurred in the cutting step. The relatively high retention during storage indicates high plant matrix stability. Comparing the behaviour of polyacetylenes in the two vegetables during storage, the results showed that they were slightly more retained in parsnips than in carrots. Unit operations and especially abrasive peeling might need further optimisation to make them gentler and minimise bioactive losses.     

Prospects of in ovo feeding and nutrient supplementation for poultry: the science and commercial applications—a review

In ovo supplementation of poultry embryos was first reported several decades ago, but it is only recently that concerted research has been directed at developing the technology for this process to be routinely used by the poultry industry. Although the technology of in ovo feeding was patented more than 10 years ago, it has not been widely adopted by the poultry industry. This review examines the early development of the enteric system of the poultry embryo; defines and distinguishes between in ovo feeding and in ovo nutrient administration; highlights the importance of early feeding of the chick; and discusses the development of in ovo feeding technology and its effects on hatchability, growth, gut health and immune response of chicks. The range of possible nutrients that can be administered is also explored. The limitations associated with embryo development and nutrient metabolism are highlighted, leading to the prediction of the future role of in ovo feeding in the poultry industry. © 2013 Society of Chemical Industry     

Invited review: Metabolic challenges and adaptation during different functional stages of the mammary gland in dairy cows: Perspectives for sustainable milk production

Milk production of dairy cows has increased markedly during recent decades and continues to increase further. The evolutionarily conserved direction of nutrients to the mammary gland immediately after calving provided the basis for successful selective breeding toward higher performance. Considerable variation in adaptive responses toward energy and nutrient shortages exists; however, this variation in adaptability recently gained interest for identifying more metabolically robust dairy cows. Metabolic challenges during periods of high milk production considerably affect the immune system, reproductive performance, and product quality as well as animal welfare. Moreover, growing consumer concerns need to be taken into consideration because the public perception of industrialized dairy cow farming, the high dependency on feed sources suitable for human nutrition, and the apparently abundant use of antibiotics may affect the sales of dairy products. Breeding for high yield continues, but the metabolic challenges increasingly come close to the adaptational limits of meeting the mammary gland's requirements. The aim of the present review is to elucidate metabolic challenges and adaptational limitations at different functional stages of the mammary gland in dairy cows. From the challenges and adaptational limitations, we derive perspectives for sustainable milk production. Based on previous research, we highlight the importance of metabolic plasticity in adaptation mechanisms at different functional stages of the mammary gland. Metabolic adaptation and plasticity change among developing, nonlactating, remodeling, and lactational stages of the mammary gland. A higher metabolic plasticity in early-lactating dairy cows could be indicative of resilience, and a high performance level without an extraordinary occurrence of health disorders can be achieved.     

Comparison of requirements for using health claims on foods in the European Union,the USA,Canada, and Australia/New Zealand

Nutrition is recognized as one of the leading factors influencing the growing incidence of noncommunicable diseases. Despite society experiencing a global rise in obesity, specific populations remain at risk of nutrient deficiencies. The food industry can use health claims to inform consumers about the health benefits of foods through labeling and the broader promotion of specific food products. As health claims are carefully regulated in many countries, their use is limited due to considerable investments required to fulfill the regulatory requirement. Although health claims represent a driving force for innovation in the food industry, the risk of misleading of consumers need to be avoided. The health claim scientific substantiation process must be efficient and transparent in order to meet the needs of companies in the global market, but should be based on strong scientific evidence and plausible mechanisms of actions, to ensure highest level of consumer protection. The objective of this review is to compare the possibilities for using health claims on foods in the European Union, the USA, Canada, and Australia and New Zealand. In particular, we focused on differences in the classification of claims, on the scientific substantiation processes and requirements for health claims use on foods in the selected regions. Reduction of disease risk (RDR) claims are associated with relatively similar procedures and conditions for use, whereas several notable differences were identified for other types of claims. In all cases, RDR claims must be approved prior their introduction to the market, and only a few such claims have been authorized. Much greater differences were observed concerning other types of claims.     

Addition of straw to the early-lactation diet: Effects on feed intake,milk yield,and subclinical ketosis in Holstein cows

This study evaluated feed intake, milk yield, and subclinical ketosis in dairy cows in early lactation fed 2 different diets postpartum. Cows are typically offered a high-energy ration immediately after calving. We compared a conventional high-energy total mixed ration (TMR) with a transition ration that contained chopped straw. We predicted that adding chopped straw would increase dry matter intake, milk production, and indicators of energy metabolism during the first 3 wk of lactation compared to cows fed a conventional high-energy TMR. We also predicted that carryover effects would be likely for at least 2 wk after treatment ended. A total of 68 mixed-age Holstein cows were enrolled in the study 3 wk before their expected calving. All cows were managed on a single high-forage diet during the dry period. At calving, cows were allocated to 1 of the 2 diets: half to the conventional high-energy TMR (CTMR; n = 34; net energy for lactation = 1.61 Mcal/kg; neutral detergent fiber = 31.7%), and the other half to a high-forage TMR containing chopped wheat straw, equivalent to 4.27% dry matter (STMR; n = 34; net energy for lactation = 1.59 Mcal/kg; neutral detergent fiber = 33.7%) for 3 wk after calving. Cows on STMR were then shifted to CTMR for the next 2 wk to study short-term residual effects on the performance of cows. Treatments were balanced for parity, body condition score, and body weight. Feed intake was measured daily from 2 wk before to 5 wk after calving using automatic feed bins. Blood was sampled twice weekly from 2 wk before to 5 wk after calving, and β-hydroxybutyrate and glucose were measured in serum samples. Subclinical ketosis was identified using a threshold of β-hydroxybutyrate ≥1.0 mmol/L in wk 1 after calving and ≥1.2 mmol/L in wk 2 to 5 after calving. Cows were milked twice daily, and weekly samples (composite samples of morning and afternoon milkings) were analyzed to determine total solids, fat, protein, lactose, and somatic cell count. Data were analyzed in 2 separate periods: the treatment phase (wk +1, +2, and +3) and the post-treatment phase (wk +4 and +5). The addition of straw to the TMR negatively affected the dry matter intake of STMR cows during wk 2 and 3 of lactation. Daily milk yield during the first 5 wk of lactation was lower in STMR cows than in CTMR cows. Concentrations of β-hydroxybutyrate were higher in CTMR cows than in STMR cows during wk 1, but this effect was reversed during wk 2 and 3 of lactation. By 21 d in milk, STMR cows had a greater risk of developing subclinical ketosis than CTMR cows. Adding chopped wheat straw to the TMR during the first 21 d after calving lowered dry matter intake and provided no metabolic or production benefits to lactating dairy cattle.     

日粮代谢能、粗蛋白质、钙和磷水平对合浦鹅养分利用率的影响

试验分育雏期和育成期两阶段进行,分别采用L9(34)正交设计探讨日粮不同代谢能、粗蛋白质、钙和有效磷水平对广西合浦鹅养分利用率的影响.结果表明:育雏期,当日粮代谢能为11.30 MJ/kg、粗蛋白质为18%、钙为1.0%和磷为0.5%时,合浦鹅对养分表观代谢率最高;育成期,当日粮代谢能为11.60 MJ/kg、粗蛋白质为15%、钙为0.7%和磷为0.5%时,合浦鹅对养分表观代谢率最高.     

Modulation of the postprandial phase by beta-glucan in overweight subjects: effects on glucose and insulin kinetics

Decreasing the postprandial glucose response is potentially of major importance to public health when low-glycemic index or high-fibre content foods are associated with a decreased risk of diabetes. We investigated in overweight subjects the effect of adding beta-glucan (BG) to a polenta (Pol) meal on postprandial metabolism and glucose bioavailability using stable isotopes. In this single-blind, randomized, crossover trial, 12 subjects ate two meals containing Pol with (Pol + BG) or without (Pol) 5 g BG. Concentrations of glucose, insulin, C-peptide, nonesterified fatty acids, triacylglycerol, total and exogenous glucose kinetics were assessed for 6 h postprandially. The kinetics of total and exogenous glucose importantly differed between the meals, but not the quantity of total and exogenous glucose appearing in plasma. Less total and exogenous glucose appeared during the first 120 min after the Pol + BG meal; the phenomenon was then reversed (both p < 0.0001). After 120 min, glucose and insulin responses declined, but remained higher after the Pol + BG meal (p < 0.05) in parallel to the inhibition of lipolysis. The endogenous glucose production (EGP) was significantly more inhibited after the Pol + BG meal. The addition of BG slowed the appearance of glucose in plasma, resulting in longer-lasting insulin secretion which exerted a prolonged inhibition of EGP and lipolysis.     

A Reappraisal of the Differences Between Scandinavian and Spanish Barleys: Effect of β‐Glucan Content and Degradation on Malt Extract Yield in the cv. Scarlett

Forty one samples of the malting barley cultivar Scarlett were collected from both Scandinavia (15 from Finland and 10 from Denmark) and the Iberian Peninsula (15 from Spain and 1 from Portugal), during the harvest years of 1998 and 1999. These samples were subjected to grain analyses, comprising protein content, hordein fractions by high performance liquid chromatography (HPLC) and β‐glucan content. The samples were micro‐malted and the malts were analysed to determine different patterns in the influence of grain composition on malt extract development linked to the two contrasting environments. The most obvious difference found between the Scandinavian and Iberian barleys was the effect of the total and insoluble barley β‐glucans. They were an effective barrier of malt extract in the North, but appeared to increase extract in the South. A conclusion was that the positive effect of β‐glucans in the Iberian barleys was a consequence of their greater capacity to synthesise and release β‐glucan hydrolases during germination.     

Glycoalkaloids in potato tubers: the effect of variety and drought stress on the α‐solanine and α‐chaconine contents of potatoes

Six varieties of Solanum tuberosum L potato grown in the Bolivian highlands under drought stress, with and without irrigation, were analysed for their content of glycoalkaloids (GAs). The plant material consisted of three drought‐tolerant varieties from a local breeding programme (PROINPA), Potosina, Chapaquita and Pampeña, and three control cultivated varieties, Malcacho, Sani Imilla and Desiree, either susceptible or relatively tolerant to drought. α‐Solanine and α‐chaconine were quantified in both the peel and flesh of the tubers. A significant increase in GA concentration (α‐solanine + α‐chaconine) was observed under drought stress conditions in most varieties; average concentration increases of 43 and 50% were registered in the improved and control cultivars respectively. In all tested cultivars, however, the GA concentration remained lower than the recommended food safety level (200 mg kg⁻¹ fresh tubers). It ranged from 52.4 to 100 mg kg⁻¹ fresh tubers in the improved cultivars and from 55.6 to 122.3 mg kg⁻¹ fresh tubers in the controls. In the improved and control varieties the α‐solanine content averaged 42.6 and 35.4% of the total potato GAs respectively and was not significantly affected by drought stress, except in Desiree. In all conditions the peel contained the greatest proportion of total GAs. The hybrid variety Pampeña (new drought‐tolerant variety) contained the lowest amounts of GAs, which were lower than those of the control varieties, with and without irrigation. © 2000 Society of Chemical Industry     

Indoor fattening of lambs raised on pasture. Part 1: Influence of stall finishing duration on lipid classes and fatty acids in the longissimus thoracis muscle

Forty male Ile-de-France lambs (10 blocks of 4 homologous lambs) were used to study the effects of four feeding systems on muscle fatty acids (FA): raising and finishing on cool-season grasses (G), raising on the same grasses and stall-finishing, indoors, on concentrates and hay, respectively, for 22 (GSS) or 41 days (GSL), and stall-feeding indoors on concentrates and hay during both growing and finishing periods (S). Twenty-four lambs only (6 blocks) were retained for comparison of growth performances, lipid content in the longissimus thoracis muscle (LT) and their FA composition according to treatment. The 16 other lambs (4 blocks) were removed from the comparison, due to a large spread in the growth of the lambs towards the end of the trial. No significant effects of treatment were seen on the rate of growth (221, 228, 243 and 245±SE 8.0g/d, respectively, for G, GSS, GSL and S groups), and the lipid contents of the LT (2.22, 2.16, 2.17 and 2.52±SE 0.11g/100g fresh tissue). Grazing, lowered n-6 PUFA (polyunsaturated fatty acids), and increased n-3 PUFA and C18:2 c9t11 (conjugated linoleic acid cis9, trans11) compared to concentrate feeding. The main effects of grazing were not removed by a short period of finish indoors on concentrate (GSS group), but C20:4 n-6 and C22:6 n-3 contents achieved the lowest contents in this group, with significant differences from the values observed for GSL and S groups (C20:4 n-6) or from the three other groups (C22:6 n-3). After a longer period of finish on concentrate (GSL group), C18:3 n-3 (linolenic acid), C18:2 c9t11 and long chain (LC) n-3 PUFA were brought to the levels observed in the S group. In terms of adequacy for human health, the C18:2 n-6/C18:3 n-3 ratios were favourably low in the four groups (2.6, 3.6, 4.9 and 5.2±SE 0.7, respectively, for G, GSS, GSL and S groups), the level observed in the case of G group being significantly lower than for the three other groups and the level observed for GSS group being significantly lower than for the GSL and S groups.     

3‐Chloropropane‐1,2‐diol (3‐MCPD) in Soy Sauce: A Review on the Formation,Reduction, and Detection of This Potential Carcinogen

Soy sauce, a dark‐colored seasoning, is added to enhance the sensory properties of foods. Soy sauce can be consumed as a condiment or added during the preparation of food. There are 3 types of soy sauce: fermented, acid‐hydrolyzed vegetable protein (acid‐ HVP), and mixtures of these. 3‐Chloropropane‐1,2‐diol (3‐MCPD) is a heat‐produced contaminants formed during the preparation of soy sauce and was found to be a by‐product of acid‐HVP‐produced soy sauce in 1978. 3‐MCPD has been reported to be carcinogenic, nephrotoxic, and reproductively toxic in laboratory animal testing and has been registered as a chemosterilant for rodent control. 3‐MCPD is classified as a possible carcinogenic compound, and the maximum tolerated limit in food has been established at both national and international levels. The purpose of this review is to provide an overview on the detection of 3‐MCPD in soy sauce, its toxic effects, and the potential methods to reduce its concentration, especially during the production of acid‐HVP soy sauce. The methods of quantification are also critically reviewed with a focus on efficiency, suitability, and challenges encountered in analysis.