辅料及微生物菌剂对羊粪好氧堆肥腐熟度的影响

好氧堆肥是目前有效的羊粪资源化利用方式,本研究旨在探究辅料及微生物菌剂对羊粪好氧堆肥腐熟度的影响。以羊粪、水稻秸秆、菌糠为堆肥原料,加入外源菌剂,检测各个处理的理化指标,生物学指标和重金属指标。平均温度Z4>Z3>Z2>Z1,最高温度68.1℃,69.1℃,69.3℃,71.1℃。pH先升高再降低,堆肥结束为8.53、8.25、8.43、8.35。C/N逐渐降低,堆肥结束为15、16、15和14。含水率逐渐下降,堆肥结束Z2含水率最低并且下降最多,为66.82%。全钾含量逐渐升高,Z4增加最大为196.58%。GI逐渐升高,50天均达到110%,Z4最先达到。NH₄⁺-N含量波动下降。重金属含量均未超过国家标准NY 525—2012。以水稻为辅料与羊粪的堆肥效果优于菌糠,混合菌与菌糠处理提前进入高温期,更有利于羊粪堆体的快速腐熟。     

产纤维素酶菌系的添加对厌氧干发酵产沼气的影响

为了提高农作物秸秆和畜禽粪便的利用率,通过在沼气厌氧发酵系统中添加降解纤维素类复合菌系,以提高产气性能。试验以玉米秸秆和牛粪为原料,在发酵温度为37℃,固体物浓度为20%,接种物含量为30%,粪草比为1:2的发酵条件下中接入1%的复合菌系进行厌氧干发酵产沼气的研究。试验结果表明由Bacillus siamensis和Bacillus subtilis subsp. Stercoris构成的复合菌系使沼气产量提高25%,甲烷产量提高55%,原料产气分别为86.4 mL/gTS和111.4 mL/gVS。试验为纤维素类生物质能的利用提供了一定的参考价值。     

杜仲叶复合工夫红茶的加工工艺研究

以杜仲叶与新鲜茶叶为主要原料,经漂烫、萎凋、揉捻、发酵及干燥等工序研制出杜仲叶复合工夫红茶。以茶叶的感官评价为评价标准,通过单因素试验和正交试验,确定杜仲叶复合工夫红茶的最佳工艺参数。结果表明,杜仲叶复合工夫红茶的漂烫工艺参数为:漂烫温度95℃,漂烫时间2 min;萎凋工艺参数为:萎凋温度30℃,萎凋湿度20%,萎凋时间3 h;人工揉捻工艺参数为:轻压10 min-重压10 min-轻压10 min;发酵工艺参数为:发酵温度30℃,发酵湿度95%,发酵时间5 h。该工艺条件下制得的杜仲叶复合工夫红茶的品质、风味俱佳。     

益生菌发酵甘薯汁的工艺优化

为改善甘薯汁口感,提高其营养价值,本文以适于发酵饮品的甘薯黄肉品种“运薯9801”和紫肉品种“漯紫4号”为原料,以乳酸菌葡聚糖明串珠菌(Polysaccharide actinomyces)为发酵菌株,研究了发酵时间、发酵温度、甘薯浆添加量、接菌量和加糖量对甘薯汁品质的影响。在单因素试验的基础上,分别构建4因素(发酵温度、发酵时间、甘薯浆添加量、接菌量)3水平的响应面设计,并建立发酵甘薯汁感官评分的二次回归方程。结果表明,益生菌发酵“运薯9801”甘薯汁的最优发酵工艺条件为:红薯浆添加量30.0%,接菌量10.4%,发酵温度34.0℃,发酵时间为36.0 h,加糖量为10.0%;益生菌发酵“漯紫4号”甘薯汁的最优发酵条件为:紫薯浆添加量39.6%,接菌量9.8%,发酵温度32.3℃,发酵时间31.0 h,加糖量10.0%。品种的筛选及工艺的优化可为发酵甘薯汁的研发提供指导。     

芦笋-灵芝发酵型饮料制备工艺研究

为提升芦笋的利用价值,以芦笋作为液体培养基,灵芝作为菌种,研究芦笋-灵芝发酵型饮料制备工艺,采用单因素试验和响应面法确定最佳稳定剂配比和调味剂含量。采用水提醇沉法提取发酵型饮料中的多糖,并用苯酚-硫酸法测定其总多糖含量。结果显示:当添加0.05%黄原胶、0.15%羟甲基纤维素钠(CMC-Na)、0.4%的β-环状糊精时,沉淀率最低(0.098%),发酵液稳定性最好。单因素和响应面试验确定调味剂最佳配比为:蜂蜜2.09%,蔗糖4.15%,柠檬酸0.10%,此时饮料多糖含量为3.262 mg/mL。该工艺条件下制备的饮料口感、风味及色泽最佳。     

干湿耦合厌氧发酵工艺设计与发酵特性试验

针对目前大中型沼气工程存在原料单一及沼液沼渣处理难的问题,提出了干法发酵与湿法发酵相结合的干湿耦合厌氧发酵工艺,即畜禽粪便采用湿发酵,将湿法发酵产生的沼液沼渣与秸秆混合进行干法发酵.并研究了干湿耦合比例——沼液沼渣与秸秆比例(BRSR)及干法发酵渗滤液回流对发酵特性的影响,结果表明,随着湿干比例的增加启动时间缩短、产气量增加;干法发酵的渗滤液总固体质量分数为1％以下,达到了固液分离的效果,有利于循环利用和喷淋,解决了湿法厌氧发酵沼液沼渣处理难的问题,实现了沼液的循环利用.     

浅玫瑰色链霉菌壳聚糖酶罐发酵工艺及其优化

发酵罐装填系数0.6,控制罐压0.08 Mpa,采用单因素试验方法考察搅拌转速、种子液OD600、接种量和通气量4个因素对壳聚糖酶发酵的影响。根据试验结果确定该菌种10 L发酵罐发酵条件:搅拌转速250 r/min,种子液OD600=0.8~1.0,通气量2.0 vvm,接种量3%,其发酵周期56 h,酶活力在52 h达到最大,为(35.2±0.5)U/mL。补料工艺发酵周期为64 h,酶活力在60 h达到最大,为(46.4±0.5)U/mL。补料工艺能维持产酶期菌丝形态和延长产酶时间,从而提高产酶,最终补料工艺比批次发酵产酶提高了32%。该研究为壳聚糖酶工业化生产奠定了基础。     

Preparation nutritional value and acceptability of barleyrabadi — an indigenous fermented food of India

Rabadi fermentation of barley flour-buttermilk mixture (fresh and autoclaved) at 30, 35 and 40°C for 6, 12, 18, 24 and 48 h lowered pH, enhanced titratable acidity and did not change fat and total mineral (Ca, Fe, Cu, Zn, Mn and P) content. Protein content of fermented fresh as well as autoclaved barley flour-buttermilk mixture either decreased or remained unchanged.Rabadi prepared from both types of barley flour at different temperatures and time periods was acceptable; but that which was fermented at 40°C for 48 h was less acceptable in terms of taste.     

Characteristics of baled silage made from first and second harvests of wilted and severely wilted forages

First and second harvests of lucerne (Medicago sativa L.), perennial ryegrass (Lolium perenne L.) and a lucerne–perennial ryegrass mixture [80 or 144 g kg^?1 dry matter (DM) of ryegrass] at the first and second harvests were cut and conditioned, wilted to 500 or 700 g DM kg^?1 then baled and stretch‐wrapped for silage on the same dates. Lucerne bales were denser (411 kg m^?3) than bales of perennial ryegrass (331 kg m^?3) (P < 0·05). After an 8‐month storage period, silage made from high DM‐content forage had a higher concentration of neutral‐detergent fibre (NDF) and was less digestible than that made from low DM‐content forage. Daily DM intakes by beef steers, when the silages of the second harvest were fed ad libitum, were 31·2, 31·2 and 22·3 g kg^?1 live weight for lucerne, lucerne–perennial ryegrass mixture and perennial ryegrass silages, respectively (P < 0·01), when the herbage had been wilted to 500 g kg^?1. In vivo digestibility of NDF in the lucerne–perennial ryegrass mixture silage (0·587) was significantly lower than that of perennial ryegrass silage (0·763) but higher than lucerne silage (0·518). Higher intakes of baled lucerne silage tended to offset its lower digestibility values. Lucerne–perennial ryegrass mixture silage had a higher DM and NDF digestibility than lucerne silage, indicating perhaps the presence of associative effects.     

Reduction of (E)-2-nonenal and (E,E)-2,4-decadienal during sourdough fermentation

(E)-2-Nonenal and (E,E)-2,4-decadienal are key aroma compounds in wheat bread crumb. The fate of these unsaturated aldehydes in sourdoughs fermented with homo- and heterofermentative lactobacilli or baker's yeast was investigated, and the metabolic pathways in these microorganisms identified. Clear differences were observed between homofermentative lactobacilli, heterofermentative lactobacilli and Saccharomyces cerevisiae. Heterofermentative strains rapidly reduced the concentrations of these aldehydes in dough, whereas S. cerevisiae displayed a lower activity. Lactobacillus sanfranciscensis reduced the aldehydes to the corresponding unsaturated alcohols, whereas S. cerevisiae reduced both the aldehyde moiety and the double bond, resulting in the formation of the corresponding saturated alcohols. S. cerevisiae first reduced the aldehyde moiety and then the double bond. In L. sanfranciscensis, the reduction of aldehydes is coupled to the oxidation of NADH to NAD⁺, which enables this heterofermentative strain to produce additional ATP from glucose. L. sakei, a strain that produces only lactic acid during sourdough fermentation, did not metabolise the unsaturated aldehydes at all. Both L. sakei and S. cerevisiae appeared to enhance aldehyde formation during the first hours of dough fermentation, probably due to the hydrogen peroxide production by these two strains.