鲜食糯玉米真空保鲜技术研究

本文通过对鲜食糯玉米真空保鲜技术的研究,确定原料最佳采收期为授粉后22-24d,不同漂烫时间和灭菌试验结果表明,以8-10min漂烫效果最佳,采用10-30-反压冷却/121℃灭菌公式,可使产品在常温下保存期达一年以上。     

不同保鲜方式下鲜食玉米品质变化规律的研究

目的 探索不同贮藏方式下鲜食玉米各品质指标的变化规律。方法 针对不同类型鲜食玉米（甜玉米、糯玉米和甜糯玉米）,选取常温（25℃）、保鲜温度（4℃）2种温度下真空包装（蒸煮、非蒸熟）、普通保鲜袋、特制袋子、仪器等不同处理,通过试剂盒测定不同处理下氨基酸、淀粉、糖类的变化趋势和规律。结果 甜玉米蒸煮后氨基酸含量更高,而糯玉米和甜糯玉米蒸煮后氨基酸含量降低;甜玉米蒸煮后可溶性糖和葡萄糖含量变高,糯玉米蒸煮后蔗糖含量变高,甜糯玉米蒸煮后果糖、葡萄糖和蔗糖含量变高;短期保鲜时,可以采用4℃真空和4℃特制袋子+保鲜剂+吸水纸两种处理,中长期保鲜时,可采用4℃蒸煮后进行真空保存,该方法优于非蒸煮。结论 甜玉米、糯玉米和甜糯玉米在不同保鲜时间、不同处理间各指标的变化趋势不同,4℃真空+保鲜剂+吸水纸和4℃特制袋子+保鲜剂这2种处理相比而言则起不到最优的作用,说明短期保存中,4℃真空已不需要额外添加保鲜剂,而4℃特制袋子+保鲜剂处理中一定要添加吸水纸,否则保鲜效果将变差。     

鲜食紫糯玉米护色保鲜工艺研究

以新鲜紫糯玉米为原料,用柠檬酸、亚硫酸钠、维生素C、三聚磷酸钠保鲜剂对其进行护色保鲜,并分析预煮时间、冷却方法和光照对保鲜效果的影响,通过正交试验得出紫糯玉米的最佳护色保鲜工艺。研究结果表明:柠檬酸添加量0.20%、亚硫酸钠添加量0.06%、三聚磷酸钠添加量0.11%、维生素C添加量0.06%;紫糯玉米预煮时间10 min,冷却方法选取自然冷却,真空包装灭菌后采用避光保存可使紫糯玉米的护色保鲜效果达到最好。     

微波食品包装技术的研究分析

微波在食品及包装上的应用1.在食品方面的应用 (1)麦片、奶粉、骨髓粉、洋参、等产品的灭菌、保鲜。 (2)无油速食面,节油速食面生产。 (3)月饼、豆粉、糕点、调味品烘干、灭菌。 (4)口服液、饮料、啤酒、牛奶、豆奶快速低温灭菌、保鲜。 (5)肉脯、肉松、肉干、鱼虾的快速低温干燥、保鲜、灭菌。 (6)鱼肉熟食、卤味、腐乳、榨菜、酱菜灭菌、保鲜。 (7)食品的焙烤、二次调味等加工(如:马铃薯片、鱼片、海苔等调味干燥)。 (8)真空(或冷冻)脱水食品、水果、蔬菜生产。     

辇上坡腊羊肉真空包装畅销四方

以生产“辇上坡”腊牛羊肉闻名遐迩的西安市食品总公司老童家牛羊肉加工厂,采取现代真空灭菌包装技术,克服产品保质期短、不易携带储藏的诸多不足,使产品闯出潼关,西渡玉门,远销四面八方。该厂1995年投资30多万元,改造了加工场地,增加了生产设备,对产品实行灭菌真空包装,使产品在常温下保鲜180天。产品在加工制作过程中,不使用色素、     

酱腌菜保鲜的初步研究

本文探讨了在空气和隔绝氧条件下，异抗坏血酸、AOB抗氧保鲜液及其混合液的抗氧化褐变和防霉能力，比较了室温（25℃）和加热（40℃）情况下异抗坏血酸和AOB保鲜液对酱腌菜的保鲜效果和组织状态变化，并分析了发生褐变的原因。实验结果表明：真空保藏时，2％异抗坏血酸液在室温和加热（40℃）条件下都能明显加速酱腌菜褐变，但抑制霉菌效果较好；在有氧情况下，异抗坏血酸没有抑菌效果。而在无论有无氧的情况下，2％AOB保鲜液对酱腌菜的抗氧化报变和防霉性都甚佳，能大大延长酱腌菜保鲜期。酱腌菜组织状态劣变随着其褐变程度的增加而加剧。     

不同灭菌包装方式对特色烤肉制品保质期的影响

通过感官评价结果对比分析透明包装和铝箔包装2种不同的包装材料以及真空、真空二次煮沸、真空高压灭菌、真空远红外灭菌等4种灭菌方式对云南保山特色烤牛肉保质期的影响。结果表明,经过二次煮沸后可明显延长预包装肉制品的保质期至30 d,且产品的感官指标最佳;使用高压灭菌的食品保质期最长为90 d以上,但感官指标不理想;远红外线灭菌对烤牛肉的保质期延长效果不明显。综上所述,二次煮沸可有效延长肉制品的保质期,且感官指标理想,不用额外增加设备,为小型肉品加工企业理想的灭菌方式。     

二次灭菌保鲜奶生产技术

二次灭菌保鲜奶是牛奶经超高温灭菌、灌装、再经第二次灭菌的瓶装保鲜牛奶。文中介绍了二次灭菌保鲜奶生产流程与工艺条件。在阐述消费奶与超高温灭菌奶后，指出我国应发展二次灭菌保鲜奶及其生产设备。     

天津开发出系列微波能设备

食品的灭菌和保鲜是食品加工行业的一个重要方面.传统加热、灭菌工艺主要依靠热力(热蒸气、红外线、热空气)通过热传导、热对流、热辐射三个途径对物料加热,这种由     

彩色糯玉米的护色保鲜加工工艺

工艺主要研究彩色糯玉米的护色、保鲜技术。实验表明:以柠檬酸0.15%、Vc0.06%、亚硫酸钠0.06%、食盐0.12%、Ca(OH)20.03%的护色溶液预煮彩色糯玉米,即可以有效地抑制彩色糯玉米变色、失去原有光泽的现象,随后采用复合包装袋进行真空包装,可以得到能够长期保鲜的产品。     

玉米深加工综合利用的前景

本文重点介绍用玉米作原料的淀粉行业、发酵酒精行业利用其生产中的副产品———玉米胚芽提取高质量保健食用油     

甜玉米及其加工品营养特点与食用品质评价研究进展

近年来,我国甜玉米栽培面积和产量均大幅提高;但甜玉米加工技术及产品品质评价工作则相对滞后。该文对国内外甜玉米及其加工产品营养和食用品质研究进展进行综述,并针对我国目前加工产品形式单一、研究基础薄弱等状况提出展望。     

Performance of lactating dairy cows fed ryegrass silage and corn silage with ground corn, steam-flaked corn, or hominy feed

Forty-eight mid-lactation Holstein cows were used in a 6-wk completely randomized block design trial with a 4 × 3 factorial arrangement of treatments to determine the effects of feeding different proportions of corn silage and ryegrass silage with supplemental ground corn (GC), steam-flaked corn (SFC), and hominy feed (HF) on the performance of lactating dairy cows. Forage provided 49% of the dietary dry matter in the experimental diets, which were formulated to meet National Research Council requirements. Ryegrass silage provided 100, 75, 50, or 25% of the total forage dry matter, with corn silage supplying the remainder. There were no interactions between the proportion of forage provided by ryegrass silage and energy supplement. Dry matter intake and milk protein percentage decreased linearly with increasing proportions of ryegrass silage, but milk protein yield was similar among forage treatments. There were no differences among forage treatments in milk yield, milk fat percentage and yield, and energy-corrected milk yield. Dry matter intake was higher and there was a tendency for increased milk fat percentage for GC compared with SFC or HF. No other differences were observed in milk yield or composition among energy supplements. Plasma urea nitrogen and glucose concentrations were similar among treatments. Under the conditions of this trial, our results indicate that feeding a combination of corn silage and ryegrass silage is more desirable than feeding ryegrass silage alone, whereas supplementation with GC, SFC, or HF supports similar levels of milk production.     

Performance of dairy cows fed annual ryegrass silage and corn silage with steam-flaked or ground corn

Twenty-four lactating Holstein cows were used in a 6-wk randomized block design trial with a 2 × 2 factorial arrangement of treatments to determine the effects of feeding ground corn (GC) or steam-flaked corn (SFC) in diets based on either annual ryegrass silage (RS) or a 50:50 blend of annual ryegrass and corn silages (BLEND). Experimental diets contained 49.6% forage and were fed as a total mixed ration once daily for 4 wk after a 2-wk preliminary period. No interactions were observed among treatments. Cows fed BLEND consumed more dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) than those fed RS, but total-tract digestibility of OM, NDF, and ADF was greater for RS than for BLEND. No differences in nutrient intake were observed among treatments during wk 4 when nutrient digestibility was measured, but digestibility of DM and OM was greater for SFC than for GC. Cows fed BLEND tended to produce more energy-corrected milk than those fed RS, resulting in improved efficiency (kg of milk per kg of DM intake). When diets were supplemented with SFC, cows consumed less DM and produced more milk that tended to have lower milk fat percentage. Yield of milk protein and efficiency was greatest with SFC compared with GC. Blood glucose and milk urea nitrogen concentrations were similar among treatments, but blood urea nitrogen was greater for cows fed GC compared with those fed SFC. Results of this trial indicate that feeding a blend of annual ryegrass and corn silage is more desirable than feeding diets based on RS as the sole forage. Supplementing diets with SFC improved performance and efficiency compared with GC across forage sources.     

Effect of feeding a corn hybrid selected for leafiness as silage or grain to lactating dairy cattle

A leafy corn hybrid was compared to a grain corn hybrid as silage and high moisture grain to evaluate dry matter intake, milk yield, and milk composition. Sixteen multiparous Holstein cows averaging 97 DIM were used in a feeding trial based on 4 x 4 Latin squares with 21-d periods. Each of four diets contained (dry basis) 8% chopped hay, 42% corn silage, 11% high moisture corn grain, 10% whole, fuzzy cottonseed, and 29% protein concentrate. One diet used leafy corn as both high moisture grain and silage. A second diet contained grain corn hybrid (control) as both high moisture grain and silage. A third diet contained leafy corn for high moisture grain and control corn for silage and the fourth diet used control corn for high moisture grain and leafy corn for silage. Cows fed diets containing leafy silage produced more milk and milk protein and ate more DM than cows fed control silage. The corn hybrid used for high moisture grain did not influence milk yield or composition. Dry matter intake was greater for cows fed the diet containing both leafy high moisture grain and leafy silage than for cows fed both control high moisture grain and control silage, but milk yield and composition were not different. When fed as silage, the leafy corn hybrid used in this experiment supported greater DMI as well as higher milk and protein yields when compared to the grain corn hybrid.     

Lactation performance of dairy cows fed rehydrated and ensiled corn grain differing in particle size and proportion in the diet

Rehydrated and ensiled mature ground corn has high ruminal starch digestibility, but particle size (PS) and dietary starch proportion (ST) can affect starch digestion and lactating cow performance. We evaluated the effect of rehydrated and ensiled corn (REC), PS, and ST on intake, lactation performance, nutrient digestibility, ruminal fermentation profile, and chewing behavior of dairy cows. Kernels from an 84% vitreousness hybrid were finely (FN) or coarsely (CS) ground, yielding geometric mean particle sizes of 1,591 and 2,185 µm, respectively. Ground kernels were rehydrated [60% dry matter (DM)] and ensiled in 200-L buckets for ≥205 d. The grinding rate (t/h) was 3.9 for FN and 11.7 for CS. The PS did not affect DM loss (11.3% of ensiled) or silage pH (3.8). Samples of each bucket (n = 15/PS) before and after silage fermentation were incubated in situ for 0, 3, 6, 18, and 48 h in 4 rumen-cannulated lactating cows. Ensiling increased the effective ruminal in situ DM degradation (63.7 vs. 34.1%), regardless of PS. Sixteen Holstein cows (152 ± 96 d in milk) in 4 × 4 Latin squares (21-d periods) were individually fed a 2 × 2 factorial combination of low (LO) or high (HI) starch diets with FN or CS. Cows were fed the same REC incubated in situ. Varied concentration of starch in the diet (29.2 vs. 23.5% of DM) was achieved by partial replacement of REC (22.0 vs. 14.2% of DM) with citrus pulp (0 vs. 8.2% of DM). Milk, protein, fat, and lactose yields did not differ. Milk fat percentage was reduced and protein percentage was increased by HI. Treatment FN increased feed efficiency (energy-corrected milk/digestible organic matter intake) when fed with HI. Total-tract starch digestibility tended to be reduced by CS (96.4 vs. 97.2% of starch intake). Serum β-hydroxybutyrate was increased by LO. High-starch diet reduced the molar proportions of acetate and butyrate in ruminal fluid and increased propionate and isoacids. Particle size did not affect ruminal fermentation profile. Coarse grinding reduced plasma d-lactate concentration with HI. Diet HI reduced the proportion of daily intake from 1900 to 0700 h and induced preferential intake of feed particles <8 mm and greater refusal of particles >19 mm in the morning. Fine REC reduced rumination time per day and increased eating time per DM intake. Milk and plasma urea-N did not differ. Ensiling of mature flint corn for >200 d largely eliminated the effect of the PS of REC on the studied outcomes. The proportion of REC in the diet affected ruminal fermentation profile and milk solids concentration, but did not affect short-term performance and digestibility. Coarse grinding of REC may allow increasing the grinding rate and thus save labor and energy during ensiling.     

甜玉米乳饮料的研制

报导了乳熟期甜玉米乳饮料的制作。最佳工艺参数为料∶水 =1∶ 1 0 ,p H5 5 ,SE0 0 5 % ,海藻酸钠0 0 5 % ,微波杀菌 85 0 W,3min。并对其质量进行了评价 ,建立了危害分析关键控制点 ( HACCP) ,为工业生产甜玉米乳饮料的产品质量的监控提供了依据。     

Corn bran versus corn grain at 2 levels of forage: Intake,apparent digestibility,and production responses by lactating dairy cows

The objective of this study was to determine the effect of substituting corn bran (CB) for dried ground corn grain (CG) in the nonforage portion of high-forage (HF) and low-forage (LF) diets. Twelve multiparous and 12 primiparous Holsteins were assigned to 4 diets using six 4 ×  Latin squares with 3-wk periods. Forage was 64 or 38% of the total mixed ration (% of dry matter). On a dry matter basis, the HFCG diet had 20% CG, the LFCG diet had 39% CG, the HFCB diet had 19% CB, and the LFCB diet had 38% CB. Digestible organic matter intake (OMI) and milk energy yield were lower for CB compared with CG within forage level. Digestible OMI was greater (1.9 kg/d) for the LFCG compared with the HFCG treatment. When CB replaced forage (LFCB vs. HFCB), digestible OMI was not different but milk energy yield was greater with the LFCB diet. The LFCG diet supported the greatest milk, milk protein, and milk energy yield. Decreased concentration of milk protein and increased concentration of milk urea nitrogen when feeding CB compared with CG suggests that lack of fermentable energy in the CB diets may have limited rumen microbial protein synthesis. Total substitution of CG with CB in the nonforage portion did not support maximum milk production, even when forage was reduced at the same time (HFCG vs. LFCB). Predicted neutral detergent fiber (NDF) digestibility at 1 times maintenance, based on chemical analysis of the individual feeds, was 22 percentage units greater for CB than for the forage mix (68.9 vs. 46.9%). In vitro NDF digestibility (30 h) was 19.4 percentage units greater for CB than for the forage mix (68.9 vs. 49.5%). However, in vivo NDF digestibility of the diet when CB replaced forage (HFCB vs. LFCB) was similar (44.1 vs. 44.5%). Similarly, predicted total digestible nutrients at the production level of intake, based on chemical analysis, were greater for the CB treatments and lower for the CG treatments than those observed in vivo.     

玉米联产品工艺浅探

玉米联产品有:精制玉米粉、精制玉米糁、玉米油、玉米快餐粉等。本文介绍了玉米联产品加工工艺,包括玉米清理、破糁脱胚、压胚制粉、综合加工等部分的工艺流程、主要设备。     

Transgenic Maize

Transgenic maize for commercial production currently confers either insect resistance or herbicide tolerance or a combination of these traits. The introduction of transgenic maize has resulted in an increase in maize production. Effects of these transgenic plants on non‐target insects, soil, and animals consuming them have been studied, and in general these effects are small. The economic impact of transgenic maize into the global market has been tremendous because maize can no longer be marketed as a simple commodity. Identity preservation and tracking systems are now required to ensure that maize meets the tolerance levels set by different countries for content of transgenic maize.