提高金川矿山下向采场采矿生产能力技术研究

几十年连续开采,金川矿山龙首矿的富矿接近枯竭,贫矿成为主要开采对象。提高采矿生产能力,实现以规模求效益是贫矿开发利用的必由之路。以金川龙首矿Ⅲ矿区贫矿开发为工程背景,探讨提高进路分层充填采矿法生产能力的关键技术。首先,以采用大型采矿设备为主要手段,进行了下向分层充填法采矿中的大断面进路参数优化、稳定性分析和分层道优化布置研究。然后,开展了进路分层充填法采矿的回采工艺参数优化。通过大断面进路采矿和优化的回采工艺,不仅提高了采矿生产能力,而且还确保了采矿安全生产,由此获得了显著的经济效益和社会效益。     

THE INFLUENCE OF ADDITION OF DEFATTED BLACKCURRANT SEEDS ON PRO‐HEALTH CONSTITUENTS AND TEXTURE OF CEREAL EXTRUDATES

ABSTRACT

Extrudates used in the study were prepared on the base of cornmeal (100%) – control, which was in 10, 30 and 50% replaced by defatted seeds of blackcurrant, which were a by‐product of supercritical fluid extraction, used for oil production. The aim of the study was to check the influence of the level of defatted blackcurrant seeds, on texture and chemical composition of the obtained extrudates. Special attention was paid to pro‐health constituents, i.e., dietary fiber, polyphenols, flavonoids and anthocyanins. The addition of defatted seeds resulted in an increase of polyphenol content, and antioxidant activity, and the rise in the level of flavonoids and soluble dietary fiber as compared with control. The enrichment of extrudates in pro‐health components, as well as improvement of sensory score, suggests that 10% addition of defatted blackcurrant seeds is a suitable level for preparation of extruded fruit‐cereal snacks.

PRACTICAL APPLICATIONS

The study demonstrates that defatted blackcurrant seeds could be a good, natural source of bioactive components in cereal snacks produced by extrusion. The suggested level of this component, optimal from sensory and dietary point of view, is 10%.

     

汉麻叶总黄酮和总多酚的同步提取工艺优化及抗氧化活性

在单因素试验基础上,以汉麻叶总黄酮、总多酚提取率和对DPPH自由基的清除率为响应值,利用响应面分析法对汉麻叶总黄酮、总多酚的提取工艺进行同步优化。研究表明,乙醇体积分数、提取时间、提取温度和液料比4个因素对总黄酮、总多酚的提取率均有显著影响。根据响应面法绘制三维及等高线叠加图,应用同步优化程序,得出总黄酮、总多酚的最佳提取工艺参数为乙醇体积分数65%、提取时间133 min、提取温度60℃、液料比30:1(m L/g)。在此条件下进行验证试验,得到汉麻叶总黄酮、总多酚提取率和对DPPH自由基的清除率分别为(2.01±0.22)%、(1.84±0.32)%、(77.63±2.15)%,与数学模型计算所得预测值接近。可见,响应面同步优化法对汉麻叶总黄酮、总多酚提取条件进行同时优化合理可行。     

烟叶颜色色度学指标与烤烟品质的关系分析

应用相关和逐步回归分析研究了烟叶颜色色度学指标与其品质的关系。结果表明,烟叶颜色的明度与总氮、总植物碱、糖碱比、氮碱比显著相关,受总植物碱含量影响较大;红度、色调角、总色差值均与总糖、总氮、总植物碱、糖碱比、氮碱比显著相关,受总氮、总植物碱、总糖含量影响较大;黄度与还原糖、钾显著相关,饱和度与总糖、还原糖、总氮、钾、糖碱比显著相关,二者均受钾含量的影响较大。除黄度、饱和度与评吸指标相关性不显著外,明度、红度、色调角、总色差值均与香气量、吃味、刺激性、杂气指标显著相关,其中明度、红度、色调角的测定结果最能反映出香气量、吃味、刺激性3项评吸指标的品质情况。     

β-葡聚糖酶降解黑木耳多糖工艺研究

为降低黑木耳多糖的分子量,提高黑木耳多糖的利用率,采用β-葡聚糖酶对黑木耳多糖进行酶解试验.在单因素试验基础上,采用正交试验确定最佳酶解工艺条件,得出4种因素对β-葡聚糖酶的活力影响顺序:加酶量>酶解pH值>酶解时间>酶解温度,最优工艺条件:加酶量700 U/g、酶解pH5.2、酶解时间2 h、酶解温度30℃,在该条件...     

豆浆制备过程中大豆脂肪氧化酶的抑制与豆腥味量的关系

探讨大豆加工制备豆浆的过程中,有效抑制大豆脂肪氧化酶对降低豆腥味量的影响,为生产低含量豆腥味的豆浆提供理论与技术支持.通过抑制大豆脂肪氧化酶实验,即热水研磨大豆、热处理或化学处理大豆原料后再沸水研磨、大豆脱皮后隔氧研磨,对得到的豆浆样品采用静态顶空气相色谱质谱法测定13种豆腥味物质,比较定量数据获得最佳抑制脂肪氧化酶的...     

新疆哈萨克族传统发酵驼乳中乳酸菌的分离鉴定

分别从新疆玛纳斯、乌兰巴依、南山、水西沟采集的4份酸驼乳中,分离得到乳酸菌22株。采用传统形态学、生理生化特性方法对乳酸菌进行鉴定,鉴定结果为Lactobacillus16株(72.72%),Lactococcus 3株(13.63%),Enterococcus 2株(9.10%),Streptococcus 1株(4.55%),优势杆菌为Lactobacillus helveticus(18.18%),优势球菌为Lactococcus lactis subsp.lactis(13.63%)。利用16S rDNA序列同源性分析和系统发育树分析对MLS1进行了分子鉴定,鉴定结果为菌株MLS1与Lactobacillus rhamnosus的同源性达到98.1%,与传统生理生化鉴定结果一致,表明了16S rDNA序列分析应用在乳酸菌鉴定上的准确性。     

苯酚-硫酸法测定瓦尼木层孔菌菌丝体多糖含量的条件优化

对瓦尼木层孔菌菌丝体多糖含量的测定进行了探讨,研究了在苯酚-硫酸法中吸收波长、显色温度、显色时间、浓硫酸用量、苯酚用量等因素对显色结果的影响。通过实验发现,最佳显色条件是波长492nm、显色温度100℃、显色时间20min、浓硫酸用量4.5mL、苯酚用量0.4mL,平均加样回收率100.7%,相对标准偏差(RSD)为0.67%。     

异形金属罐气压胀形过程仿真研究

使用钣金成形专用软件模拟异形金属罐气压胀形过程,分析金属流动、壁厚变化、应力和应变分布的规律。研究结果为异形金属罐气压胀形过程控制和进行工艺优化提供了可靠的实用信息。     

Predictive modeling of Bacillus cereus spores in farm tank milk during grazing and housing periods

The shelf life of pasteurized dairy products depends partly on the concentration of Bacillus cereus spores in raw milk. Based on a translation of contamination pathways into chains of unit-operations, 2 simulation models were developed to quantitatively identify factors that have the greatest effect on the spore concentration in milk. In addition, the models can be used to determine the reduction in concentration that could be achieved via measures at the farm level. One model predicts the concentration when soil is the source of spores, most relevant during grazing of cows. The other model predicts the concentration when feed is the main source of spores, most relevant during housing of cows. It was estimated that when teats are contaminated with soil, 33% of the farm tank milk (FTM) contains more than 3 log₁₀ spores/L of milk. When feed is the main source, this is only 2%. Based on the predicted spore concentrations in FTM, we calculated that the average spore concentration in raw milk stored at the dairy processor during the grazing period is 3.5 log₁₀ spores/L of milk and during the housing period is 2.1 log₁₀ spores/L. It was estimated that during the grazing period a 99% reduction could be achieved if all farms minimize the soil contamination of teats and teat cleaning is optimized. During housing, reduction of the concentration by 60% should be feasible by ensuring spore concentrations in feed below 3 log₁₀ spores/g and a pH of the ration offered to the cows below 5. Implementation of these measures at the farm level ensures that the concentration of B. cereus spores in raw milk never exceeds 3 log₁₀ spores/L.