Freeze drying technique for microencapsulation of Garcinia fruit extract and its effect on bread quality

Microencapsulation is an enduring technology for protection and controlled release of food ingredients. The Garcinia cowa fruit rinds are rich source of (−)-hydroxycitric acid (HCA), which is reported to have various health benefits. But, HCA is hygroscopic in nature and thermally sensitive. Hence, G. cowa fruit extract was microencapsulated using three different wall materials such as whey protein isolate (WPI), maltodextrin (MD) and combination of whey protein isolate and maltodextrin (WPI + MD in 1:1 ratio) by freeze drying at 30% concentration. The microencapsulated powders were evaluated for their impact on bread quality and free HCA concentration. The microcapsules exhibited wider particle size range of 15–100 μm and HPLC analysis showed that all the three encapsulates yielded higher free (above 85%) and net (above 90%) HCA recovery. Moreover, bread with WPI encapsulates exhibited higher volume, softer crumb texture, desirable colour and sensory attributes and had higher free HCA concentration. This indicated that WPI has excellent encapsulation efficiency than other two wall materials during bread baking.     

质构分析(TPA)及测试条件对面包品质的影响

简要介绍了质构分析(TextureProfileAnalysis)的方法,具体阐述了TPA质构参数的含义,并对面包片进行TPA测试,研究压缩速率和压缩程度对测试结果的影响。结果表明,压缩程度对考察的五个质构参数有显著影响,压缩速率对弹性和内聚性影响显著。     

超声协同大豆分离蛋白对米粉和米面包品质的影响及机制研究

目的 探究超声协同大豆分离蛋白(soybean isolate protein, SPI)对米粉以及米面包品质的影响。方法 以碎米为主要原料，5个梯度（0%、3%、6%、9%、12%，以碎米粉质量计）的大豆分离蛋白(soybean isolate protein, SPI)为辅料，比较超声协同5个梯度SPI对混合粉热机械学特性、糊化特性、流变特性以及米面包比容、损耗率、感官评价的影响。结果 与未进行超声处理的样品相比，超声协同SPI处理的米粉的吸水率从64.90±0.00增加至94.80±0.00，其混合粉的峰值黏度从2704.00±47.76降低至1567.00±116.73，表明超声使淀粉部分支链断裂，生成大量短直链淀粉，导致分子量下降，相互作用减弱；超声处理后的样品G′曲线呈现出先增加后降低的趋势，G''曲线随着SPI含量的增加呈现出逐渐降低的趋势。当SPI添加量为9%时，米面包的比容达到最大值，为0.86±0.08，感官评分从50.05±3.75增加至86.27±2.28分；当SPI添加量达到12%时，米面包的损耗率达到最低。结论 综上所述，采用9% SPI的方法制备米面包，可以有效的改善米面包品质，本研究为米面包在食品领域的应用提供了理论基础。     

Microencapsulation of Bifidobacterium bifidum F‐35 in Whey Protein‐Based Microcapsules by Transglutaminase‐Induced Gelation

Abstract: Bifidobacterium bifidum F‐35 was microencapsulated into whey protein microcapsules (WPMs) by a transglutaminase (TGase)‐induced method after optimization of gelation conditions. The performance of these WPMs was compared with that produced by a spray drying method (WPMs‐A). WPMs produced by the TGase‐induced gelation method (WPMs‐B) had larger and denser structures in morphological examinations. Native gel and SDS‐PAGE analyses showed that most of the polymerization observed in WPMs‐B was due to stable covalent crosslinks catalyzed by TGase. The degradation properties of these WPMs were investigated in simulated gastric juice (SGJ) with or without pepsin. In the presence of pepsin, WPMs‐A degraded more quickly than did WPMs‐B. Finally, survival rates of the microencapsulated cells in both WPMs were significantly better than that of free cells and varied with the microencapsulation method. However, WPMs‐B produced by TGase‐induced gelation could provide better protection for microencapsulated cells in low pH conditions and during 1 mo of storage at 4 °C or at ambient temperature.     

紫苏叶浸提液对面包品质的影响

按照水和紫苏叶浸提液4:1的比例,紫苏叶浸提液浓度分别为0、3%、6%、9%、12%,制作面包,研究紫苏叶浸提液对新鲜面包的感官品质、比体积以及在贮藏过程中面包的保水性、老化度、微生物生长等方面的影响。结果表明,在浓度为6%时,面包的感官品质和比体积最好。随着浓度的提高,面包的保水性、抗老化性及抑制微生物生长的能力逐渐增强。在紫苏叶浸提液浓度为12%时,保水性、抗老化性及抗微生物生长能力最好。     

Pickering乳液法制备PPI-TA-MD微胶囊及其对南瓜籽油氧化稳定性的影响

目的:改善南瓜籽油(PSO)的氧化稳定性，促进PSO的开发利用。方法:将豌豆分离蛋白(PPI)—单宁酸(TA)稳定的Pickering乳液在麦芽糊精(MD)作为填充材料存在下，通过喷雾干燥制备南瓜籽油微胶囊，探究PPI-TA-MD包埋体系对PSO氧化稳定性的影响。结果:Pickering乳液经喷雾干燥后，可得到表面光滑的球状微胶囊粉末；随着壁材中TA浓度的增加，微胶囊显示出更小的粒径[(32.00±0.28)μm],相对较低的水分含量[(1.970±0.043)%]和较高的堆积密度[(0.725±0.014) g/cm³];不同TA浓度的PSO微胶囊FFA释放率为39.63%～69.91%,且随着TA浓度增大FFA释放速率减慢；与封装在PPI中的PSO相比，用作外壳材料的PPI-TA复合物提高了PSO的热稳定性、DPPH自由基及ABTS自由基清除能力和氧化稳定性。结论:以PPI-TA-MD为壁材的微胶囊可以改善PSO的抗氧化能力和氧化稳定性。     

乳清蛋白在转谷氨酰胺酶作用下包埋益生菌的研究

为了提高双歧杆菌在人体胃肠道中的存活率,以乳清蛋白为壁材,转谷氨酰胺酶为交联剂,通过乳化凝胶的方法制备包埋有两歧双歧杆菌的蛋白质微球。实验表明:以此工艺制备的微球成球性较好,粒径为(308.2±16.2)μm,益生菌包埋率为87.8%±10.0%,与未包埋的两歧双歧杆菌比较,经过包埋后的两歧双歧杆菌在模拟胃液和高胆盐溶液中的存活率分别提高了5个和2个对数值。     

喷雾干燥法制备生姜微胶囊的研究

以生姜为原料,经乙醇提取而得的姜油树脂为心材,以阿拉伯胶和麦芽糊精为壁材,用喷雾干燥法来制取姜油树脂微胶囊。通过正交试验分析,以油树脂包埋率为指标,确定了生姜喷雾干燥法微胶囊化的最佳工艺条件:心材与壁材比为1∶5、进风温度190℃、阿拉伯胶与麦芽糊精比为1∶7。     

喷雾干燥速溶香蕉粉制备工艺研究

从全利用香蕉可食部分出发研究喷雾干燥法制备速溶香蕉粉的工艺,主要研究了干燥前果汁的浓缩与调配。酶处理后的香蕉果浆经离心分离,上清液喷雾干燥制备速溶香蕉粉。以含水量、吸湿性、溶解性、粒径、颗粒微观结构为指标考察麦芽糊精DE值、添加量、果汁浓度及抗结剂对喷雾干燥产品的影响,得到最佳工艺为:果汁浓缩至20°Brix,添加0.6(kg/kg香蕉固形物)DE15～20麦芽糊精,0.015(kg/kg香蕉固形物)SiO2。     

白果蛋白对面团特性及面包品质影向规律的研究

首先将白果蛋白按照不同比例添加到面包粉中,采用一次发酵法,经过38℃醒发,在190℃下将面团烘烤成面包.通过小米置换法、GB 5497 - 1985法和TA - Xtai质构仪分别对面包的比容、面包的水分以及面包芯的硬度进行测定,并根据《面包焙烤品质评分标准》对面包的感官进行评定,然后研究白果蛋白对面团流变特性、面包烘焙特性及面包货架期的影响规律.试验结果表明:添加一定量白果蛋白的面团吸水率增大,面团的形成时间、稳定时间和评价值增大,面团的粉力、拉伸阻力、拉力比数和延伸性也升高;添加适量的白果蛋白可改善面包的焙烤特性,增大面包的体积,提高面包的含水量,降低面包的硬度,改善面包的质地和口味,并且保持了面包在贮存过程中的水分及硬度,延长了面包的货架期.     

大豆蛋白在面包中的应用研究

通过焙烤实验,研究比较了大豆蛋白对面包焙烤质量的影响。结果表明:普通大豆蛋白在4%的用量下,对面包品质就有不良作用;但改性后的面包专用大豆蛋白粉(MSPF)的用量在8%,也表现出良好的作用。     

Optimization of encapsulation of maltogenic amylase into a mixture of maltodextrin and beeswax and its application in gluten-free bread

In this work maltogenic amylase (MAase) was encapsulated into the mixture of maltodexrin and beeswax (BW) for retarding staling of gluten-free bread. The effects of maltogenic amylase (MAase) concentration (8.2, 45, and 82 mg/ml), maltodextrin with dextrose equivalent (DE) 4–7 (MD) (1, 2.5, and 4%) and, BW (1, 2.5, and 4%) on the encapsulation efficiency (EE) of encapsulated enzyme were optimized using RSM. The optimized formulation was MAase with 8.2 mg/ml, MD 4% and BW 1%, leading to the highest EE (79.35%), thus chosen for subsequent experiments. The prepared particles were 1,190.50 nm with PDI of 0.336 and zeta potential of −8.30 mV. Surface morphologies of produced particles were almost spherical with layered appearance. Batter with this formulation led to higher cross over point in frequency sweep than free enzyme-loaded batter. Lower weight loss, higher volume index, darker crust color, whiter crumb color, more aerated microstructure, less hardness in crumb, and higher sensorial acceptability on the first day and during storage period in the breads containing encapsulated MAase was observed.     

Effects of green tea extract on the quality of bread made from unfrozen and frozen dough processes

Two different green tea extracts (GTE‐A and ‐B) as a rich source of tea catechins were incorporated into a no‐time bread‐making process, where bread made from the unfrozen and frozen dough processes was compared by specific volume and texture profile. GTE‐A and ‐B both exhibited significant effects on bread volume and firmness, but to a different extent. GTE‐A with higher content of tea catechins (73%) at a level of 1.5 g kg^?1 flour was found to lead to a significant reduction in bread volume in unfrozen dough process and an increment in firmness during storage for 4 days at ambient temperature (22 °C). GTE‐B, with a lower content of catechins (60%), had relatively mild effects on the bread quality. Significantly negative effects were evident starting at a higher level of 5.0 g kg^?1 flour in unfrozen dough process. Frozen storage showed more predominant deteriorating effects than the GTEs over a period of 9 weeks frozen storage at ?20 °C. Copyright © 2006 Society of Chemical Industry     

不同酶制剂对面包品质影响

研究葡萄糖氧化酶(GOD)、转谷氨酰胺酶(TG)、脂肪酶和真菌淀粉酶对面包比容、出品率、硬度及水分迁移影响。结果表明,葡萄糖氧化酶能增大面包体积、降低出品率、提高面包芯硬度和有效延缓贮藏期水分散失;转谷氨酰胺酶能增大面包体积、降低出品率、降低面包芯硬度,对水分保持作用不明显;脂肪酶会减小面包体积、增加出品率、明显降低面包芯硬度和保持面包芯水分;真菌淀粉酶能有效增加面包体积、降低出品率、降低面包芯硬度,对水分保持无明显作用。     

Application of whey of Mozzarella di Bufala Campana fermented by lactic acid bacteria as a bread biopreservative agent

A total of nine isolated lactic acid bacteria (LAB) from tomato and sourdough with antifungal activity were employed to revaluate the whey of Mozzarella di Bufala through the fermentation process for 72 h at 37 °C. Then, the fermented whey (BWF) was characterised and used as biopreservative in bread formulation. L. plantarum TR7 and L. plantarum TR2 strains showed average lactic acid concentration in BWF of 13.8 g L⁻¹. Also, the bread volatile organic compounds (VOC) analysis showed an increase in hexanal, benzeneacetaldehyde, benzaldehyde and pyrazine tetramethyl when using BWF as ingredient. Moreover, the DPPH-inhibitory activity of bread with BWF extract also reflected a 33% rise in comparison with control bread. The application of BWF as a biopreservation agent in bread showed an increase in shelf life compared with bread with 0.3% calcium propionate and bread control for 2 and 15 days, respectively. BWF can be used as an interesting biopreservation strategy of bread.