Application of Principal Component Analysis as Properties and Sensory Assessment Tool for Legume Milk Chocolates

Principal component analysis (PCA) was employed to examine the effect of nutritional and bioactive compounds of legume milk chocolate as well as the sensory to document the extend of variations and their significance with plant sources. PCA identified eight significant principle components, that reduce the size of the variables into one principal component in physiochemical analysis interpreting 73.5% of the total variability with/and 78.6% of total variability explained in sensory evaluation. Score plot indicates that Double Bean milk chocolate in-corporated with MOL and CML in nutritional profile have high positive correlations. In nutritional evaluation, carbohydrates and fat content shows negative/minimal correlations whereas no negative correlations were found in sensory evaluation which implies every sensorial variable had high correlation with each other.

Effects of land uses on soil physic-chemical properties and erodibility in collapsing-gully alluvial fan of Anxi County,China

the National Key Technologies R＆D Program of China during the 12th Five-Year Plan period （2011BAD31B00）

Study Properties of Fermented Camels’ and Goats’ Milk Beverages Fortified with Date Palm (<i>Phoenix dactylifera L</i>.)

Camels’ milk (CM) and goats’ milk (GM) are rich in nutrients and vitamins necessary for the health of humans and have therapeutic properties as they are rich in antioxidants and have a protective role against free radicals that have harmful effects on human health. Date palm (DP), camels’ milk and goats’ milk have been reported to be used for the prevention and treatment of various diseases in Arab countries. This study was designed to mix date palm with camels’ milk and goats’. Eight formulations of both camels’ milk and goats’ were made from different percentages of date palm. These formulations were added at ratios of 0 (control), 10%, 20% and 30% (w/v) to camels’ milk and goats’ and the effect of this date palm on the composition and texture properties of the fermented obtained products were followed. It has been found that pH, protein, fat decreased and total solid, carbohydrate, ash, viscosity, vitamins, minerals and antioxidants increased with the increase of the added percentage of date palm compared to control. Microbial counts of the fermented camels’ milk (FCM) and goats’ milk (FGM) increased significantly (P < 0.05) with the addition of different formulations and during storage. Also, fermented camels’ milk (FCM) and fermented goats’ milk (FGM) fortified with different ratios date palm (DP) concentration resulted in good properties and higher acceptable sensory values (at a rate of 10% - 20%) in fresh and till the end of storage periods. The addition of the date palm to all treatments improved the composition, viscosity, microbiological quality of fermented camels’ and goats’ milk with nutritional functional values and acceptable sensory attributes.

Effect of Camel Milk Fortified with Dates in Ice Cream Manufacture on Viscosity, Overrun, and Rheological Properties during Storage Period

The effect of using camel milk with 2 dates types (Sokary & Al-Khalas), in 3 forms (paste, pieces, and molasses), with 2 different concentrations (5% & 10%) in the manufacturing of ice cream on its viscosity, overrun%, rheological and melting properties during storage period up to 60 days at -18&#176C was studied. It was noticed that there are higher mean of viscosity values (cp) when using “Al-khalas” dates paste 5% and 10% followed by samples with “sokary” paste then samples with molasses in ice cream samples compared to those with added date’s pieces of either “Sokary” or “Al-khalas”. There are significant differences of overrun values between all treatments and samples with the added date paste of either “sokary” or “Al-khalas” which recorded the lowest values. Increased melting resistance and good qualities as heat shock and melting properties were significantly better for the samples with added dates pieces or paste unlike the molasses. The storage effect is obvious decline, especially when using dates molasses.

Esterase Activities and Biochemical Properties of Lactic Acid Bacteria Isolated from Goat＇s Milk Cheese in Argentina

Twenty-two lactic acid bacteria （LAB） strains isolated from Argentinean goat dairy products were evaluated for its biochemical properties and esterase activities relevant to flavor development. Streptococcus thermophilus （UNSE314）, Lactobacillus （L.） delbrueckii subsp, bulgaricus （UNSE309）, L. rhamnosus （UNSE308）, L. plantarum （UNSE287, UNSE316, UNSE317） and Pediococcus pentosaceus （UNSE315） strains presented high acidifying activity. All strains tested metabolized citrate and produced diacetyl-acetoin in goat milk. Based on these results, 10 strains with the best performance in diverse technological properties were selected to determine esterolytic activity. In all evaluated strains, esterase specific activity （ESA） was detected on ct-naphthyl （ct-NA） acetate and 13-naphthyl （[3-NA） acetate, propionate, eaprylate and ct-NA butyrate. No activity was detected on [3-NA laurate. The highest values were detected when using a-NA instead of fI-NA derivatives as substrate. In Pediocoecus strains, wide variability in ESA were observed, which were species- and strain-specific. These results allow us to select strains with biochemical properties and esterase activities to design starter and adjunct cultures that contribute to flavor development during cheese ripening, thus preserving the typical organoleptic characteristics of Argentinean goat cheeses.

Effect of Different Ratios of DL-type Starter Culture： Mould Geotrichum candidum on the Viscosity and Sensory Properties of Fermented Milk

A great variety of dairy products with different flavour, texture and health-promoting properties can be obtained from milk using different technologies and starter cultures. Fermented milks are consumed in many parts of the world and are relished for their acidic taste and health benefits. The aim of this study was to compare effects of different ratios of DL-type starter culture： mould Geotrichum candidum grown in milk on its viscosity and sensory properties on the 5th, 10th and 15th day of storage at 4 ~C~ in order to determine the best ratio to prepare fermented milk on basis of Iranian acceptance. We have examined the production of fermented milk by 80： 20, 70： 30, and 60：40 ratios of DL-type starter culture： mould Geotrichum candidum grown in milk. The results obtained from viscosity measurement and sensory evaluation showed no significant difference between these treatments used in the study and were not satisfactory; their viscosity was not accepted and scores attributed to odour and flavor of fermented milks by panelists were low.

Effects of tillage, fallow and burning on selected properties and fertility status of Andosols in the Mounts Bambouto, West Cameroon

To assess the impact of land use on the Andosol fertility, changes in chemical and physical properties affecting soil quality were monitored on Andosols from Mount Bambouto submitted to four different land use and management systems: natural cover, tillage, burning and fallow. In comparison with the natural cover, tillage reduces Andosol OC (6.5 to 4.8%), total N (4.51 to 2.95‰), CEC (22.0 to 20.9 cmol.kg–1) and the abundance of soil macro-aggregates expressed by the water stable aggregates (WSA) varies from 53.8 to 12.0%;and increases the bulk density (0.69 to 1.09 g.cm–3) and the sum of exchangeable cations (3.58 to 4.84 cmol.kg–1). Burning also reduces Andosol OC (6.5 to 0.8%), total N (4.51 to 0.95‰) and CEC (22.0 to 10.2 cmol.kg–1), but increases soil pH (4.62 to 6.54), the sum of exchangeable cations (3.58 to 5.74 cmol.kg–1) and the abundance of soil macroaggregates (WSA: 38.2 to 57.0%). In comparison with tillage, fallow increases Andosol OC (4.8 to 6.5%), total N (2.95 to 5.04‰), CEC (18.0 to 21.6 cmol.kg–1), the sum of exchangeable cations (3.58 to 5.05 cmol.kg–1) and the abundance of soil macroaggregates (WSA: 12.0 to 48.8%). Globally, the tillage management deteriorates Andosol chemical and physical properties affecting fertility, whereas the fallow management restores them. The burning management also improves some Andosol chemical and physical properties affecting quality, but it won’t last long.

Impact of Seasons on Soil Physico-Chemical Properties and Tea Yields Based on Enriched Sheep Manure Used in Kericho, Kenya

Tea (Camellia sinensis (L) O. Kuntze) is a perennial crop grown for beverage consumption. Its production is the leading foreign exchange earner in Kenya contributing about 26% foreign exchange and 4% GDP. Nitrogen (N), Phosphorus (P) and potassium (K) are the recommended nutrients for tea production. However, their continuous use has been reported to have negative effect on soil physico-chemical properties and health. Sheep manure has been recommended in tea production for its soil pH buffering effect and increased tea yields. However, effects of sheep manure enriched with inorganic fertilizer on tea soils and yield have not been conclusively investigated. This study was established at KALRO—Tea Research Institute Kericho in Timbilil estate to determine the impact of seasonal variation on soil pysico-chemical properties and yields on enriched sheep manure used. Randomized complete block design (RCBD) experimental design was adopted with 14 treatments replicated thrice. The treatments were: control with no fertilizer use, NPK at 180 Kgs N/ha/yr, sheep manure only and two enriched sheep manure ratios of 4:1 and 8:1 which translates to a mixture of (4:1) 4 parts of sheep manure and 1 part of D.A.P inorganic fertilizer. Same applied to 8:1 ratio, respectively at rates of 60, 120, 180 and 240 Kgs N/ha once per year. Data were subjected to ANOVA in GenStat statistical package and means separated by Duncan’s multiple range tests at P ≤ 0.05 significance level. Results obtained showed that soil physico-chemical properties and tea yields were influenced significantly (P ≤ 0.05) by treatments applied. Soil available water and organic matter were higher on enriched sheep manure 4:1 at 240 rate used while soil porosity and bulk density were not significantly affected. Total N and P, increased with enriched sheep manure ratio of 4:1 at 240 rate while K+, Ca2+, Mg2+, Mn and pH increased with sole application of sheep manure at rate 180 and enriched sheep manure 8:1 at 180 rate. Tea yields increased with enriched sheep manure 4:1 ratios at the rates of 240. The findings recommend enriched sheep manure 4:1 ratio at 240 rates to be adopted by tea farmers within Kericho region. Further studies involving different geographical locations are proposed.

复配菌株对发酵乳品质与功能特性的改善作用研究进展

发酵乳具有悠久的历史,是经乳酸菌发酵而成的,富含蛋白质、矿物质和维生素等多种营养成分。随着人们对生活品质追求的提高,发酵乳受到消费者越来越多的关注。目前市面上的发酵乳多数是以单菌株或传统乳酸菌(嗜热链球菌和保加利亚乳杆菌)作为发酵剂制备而成的,但是以此生产发酵乳会有发酵时间过长、口感略差和稳定性不佳等问题。近年来,复配菌株作为发酵乳的发酵剂成为发酵乳制备方向的研究热点,利用不同菌株间的互作协同作用,可以有效提高代谢产物的含量和丰富度,进而改善发酵乳的品质及功能特性,弥补传统发酵乳在产品形态以及感官体验等方面的不足。本文综述了复配菌株能够加快发酵乳pH下降速度,丰富产品感官以及改善其流变特性和持水能力,同时还可以增强发酵乳在降血脂、抗炎、抗氧化、抑菌等功能方面的能力。最后展望了发酵乳在未来可以进行创新的研究方向,为今后发酵乳的多元化、功能化、精准化生产提供指导。

不同热杀菌条件对羊乳乳清蛋白和酪蛋白结构与功能特性的影响

为了探究不同热杀菌条件对羊乳乳清蛋白和酪蛋白结构与功能特性的影响,选取工业常用的杀菌条件65℃、30 min,80℃、30 s,95℃、5 min和135℃、4 s处理羊乳,并分离羊乳乳清蛋白和酪蛋白;采用圆二色光谱仪、傅里叶变换红外光谱仪、荧光分光光度计、激光共聚焦扫描显微镜、原子力显微镜分析蛋白结构与特性变化情况。结果表明,65℃、30 min和80℃、30 s处理的乳清蛋白和酪蛋白结构变化较小,蛋白展开与表面疏水性的增加使得乳清蛋白和酪蛋白具有更好的起泡特性和乳化特性。95℃、5 min和135℃、4 s处理使蛋白的α-螺旋相对含量显著降低,无规卷曲相对含量显著增高,蛋白严重变性,溶解度与表面疏水性的降低会对羊乳蛋白功能特性以及稳定性产生不利影响。综上,本研究揭示了羊乳乳清蛋白和酪蛋白在不同杀菌温度条件下的变化规律,可为优化羊乳制品的品质和稳定性提供参考,有助于开发更具有功能性的羊乳产品。

发酵豆乳乳酸菌的筛选及其对豆乳抗氧化性能的改善作用

该文通过分离纯化、形态观察和16S rDNA鉴定的方法,从传统发酵食品及健康人肠道中筛选出74株乳酸菌。以胃肠液耐受性、产酸能力和增殖能力为指标,初步筛选出5株性能优良的乳酸菌,并将其应用于发酵大豆乳、花生乳和鹰嘴豆乳,进一步测定菌株在3种豆乳中的产酸和增殖能力,筛选出适用于发酵不同豆乳的乳酸菌。其中发酵24 h时,Lactobacillus fermentum LF3.2在三种豆乳中均具有最强的产酸能力,发酵大豆乳和花生乳的pH值达到4.5以下。此时三种发酵豆乳中的活菌数都达到了8 log CFU/mL以上,在大豆乳和花生乳中L.fermentum LF3.2和L.plantarum G1.3增殖能力最强,在鹰嘴豆乳中L.fermentum LF3.2和L.plantarum G1.4的增殖能力最强。三种豆乳经L.fermentum LF3.2、L.plantarum G1.3发酵24 h后其抗氧化活性均显著提高,发酵大豆乳对DPPH·和OH·的清除率比未发酵分别高出23.34%、23.64%,增长量最高。L.fermentum LF3.2更能增加三种豆乳对DPPH·的清除率,而L.plantarum G1.3更能增加三种豆乳对OH·的清除率。本文研究结果对开发功能性发酵豆乳具有一定的指导意义,为乳酸菌应用于植物基发酵食品奠定了理论基础。

不同结构人工乳脂肪球膜对婴配乳理化性质和脂肪消化特性的影响

将不同结构的人工乳脂肪球膜作为乳化剂和营养强化剂加入到婴配乳中,并以富含天然乳脂肪球膜(milk fat globule membrane,MFGM)成分的MFGM-10为对照,并通过模拟婴幼儿体外消化模型对比了其在胃和小肠消化阶段的粒径分布、电位变化和游离脂肪酸释放量等关键指标,以探究不同结构人工MFGM对婴配乳理化性质和脂肪消化特性的影响。结果表明,添加单层人工MFGM的婴配乳具有较小的平均粒径和较大的ζ-电位绝对值,同时具有较高的乳化活性指数和乳化稳定性指数,说明单层人工MFGM在改善婴配乳理化性质和提高乳液稳定性方面效果最佳。在消化结束后,各组释放游离脂肪酸总量的顺序为对照组1 560μmol/mL>双层组1 415μmol/mL>单层组1 361μmol/mL>空白组1 048μmol/mL,说明添加人工MFGM能够达到与天然MFGM相似的脂肪消化效果。该研究为人工MFGM代替天然MFGM在婴配乳中的应用提供一定理论依据。

人乳低聚糖与肠道菌群互作及其调节婴儿免疫功能的研究进展

人乳低聚糖(human milk oligosaccharides,HMOs)是母乳中的一类重要组分,迄今为止已经确定了200多种结构不同的HMOs。HMOs能在肠道微生物的作用下产生短链脂肪酸,对婴儿健康产生有益影响,这是母乳与配方粉的主要区别之一。研究表明,不同种类的肠道微生物利用不同机制来识别和消化不同结构的HMOs,维持肠道菌群平衡。同时,HMOs还具有缓解过敏症状,预防坏死性小肠结肠炎等多种功能。本文对HMOs的结构、种类与含量、与婴儿肠道菌群的互作及其免疫调节功能进行了综述。HMOs可促进婴儿肠道菌群的定植与生长,并通过多种方式直接或间接调节婴儿免疫功能。本文为HMOs在婴幼儿食品中的应用提供理论支持,对其未来研发方向提供新思路。

发酵乳稳定性及其影响因素研究进展

文章探讨了乳基质成分、加工工艺、发酵菌种及功能性成分的添加对发酵乳稳定性的影响。发酵乳较低的稳定性易导致不理想的质地和风味,降低消费者接受度。总固体和蛋白质含量的提高会增加发酵乳的黏度、稠度以及持水力,脂肪的含量以及粒径大小都会影响发酵乳质地。未加热和严重热处理的乳会比最佳热处理的乳更容易脱水收缩,在较高压力和热处理后的均质化过程有助于减少脱水。搅拌5 min,38℃下平滑,并在管式换热器(THX)中冷却的联合操作,可以改善搅拌型酸奶储存过程中的硬度、黏度和稠度。0℃冷却能够改善凝胶性能,缩短冷却时间,节省时间和能源。此外,分泌EPS的发酵剂可以有效地提高保水能力,改善乳清分离,为发酵乳的品质提升提供参考。

干法脱胶对亚麻籽植物乳稳定性和营养特性的影响

为探究亚麻籽胶对亚麻籽植物乳的稳定性、营养特性的影响,本研究对亚麻籽进行干法脱胶,并全面探究了不同脱胶率对亚麻籽植物乳营养素溶出和稳定性的影响,对不同样品的粒径、zeta电位、粘度、Turbiscan稳定性指数、流变性能、微观结构、总固形物含量、总酚含量和蛋白含量进行了测定和分析。结果表明,与未脱胶的亚麻籽所制亚麻籽乳相比,脱胶后亚麻籽乳的电位绝对值增大且粒径、稳定性指数和粘度均变小,其中脱胶率为4.0%的亚麻籽植物乳电位绝对值由26.72 mV增大至29.60 mV,D[4,3]由34.90μm减小至22.60μm,粘度降低了9.95%,且表现出剪切稀化行为,液滴分布均匀。脱胶率为6.30%的亚麻籽植物乳的总固形物含量提高了5.03%,达到7.73 g/100 mL,蛋白含量提高了18.78%,达到2.15 g/100 mL,表明亚麻籽经适度脱胶后能够提高亚麻籽植物乳的稳定性,促进蛋白质等营养素溶出,相关研究结果为亚麻籽高值化、全值化加工利用提供参考依据。

超声处理对山羊奶酪蛋白理化和功能特性的影响

以山羊奶酪蛋白为原料,利用不同强度超声处理山羊奶酪蛋白,探究超声处理对山羊奶酪蛋白的pH和电导率、Zeta电位、浊度等理化指标以及乳化性和起泡性等功能特性的影响。结果表明,与未处理相比,超声处理后山羊奶酪蛋白pH下降,电导率变化不显著(P>0.05);Zeta电位绝对值在400 W处理2 min时达到最大值27.85±1.55 mV;浊度值与未处理相比显著性降低(P<0.05);与未处理相比,超声处理可以减小蛋白平均粒径,并在700 W处理6 min时达到最低值,由383.20±13.07 nm减少至176.17±4.28 nm;扫描电镜结果表明超声改变了酪蛋白原有表观形态,导致不规则碎片的产生;超声处理后的酪蛋白乳化性在100 W处理10 min时提高了41.44%。在400 W处理10 min时起泡性和泡沫稳定性显著增加(P<0.05),分别达到最大值32.88%±0.07%和91.93%±0.19%。综上,超声处理产生的空化效应以及机械作用可以为山羊奶酪蛋白提供更好的理化特性和功能特性。

微波预处理对黑芝麻乳稳定性的影响

以黑芝麻为研究对象,探究了微波预处理时间(0~12 min)对黑芝麻物性特征和全籽乳稳定性的影响。结果表明:微波预处理会诱导黑芝麻体积膨胀,外种皮呈凹凸不平状,其中微波预处理12 min时,外种皮发生破裂;微波预处理显著降低了黑芝麻的硬度、弹性、胶黏性和回弹性(P<0.05),其中微波预处理9 min时,均达到最小值;随着微波预处理时间的延长,黑芝麻乳的平均粒径从1.21μm增加至1.52μm(P<0.05),Zeta-电位从-26.90 mV降低至-31.91 mV(P<0.05),并伴随着物理稳定性的明显提升,以微波预处理9 min时效果最佳,表现为Turbiscan稳定性指数(TSI)曲线斜率明显降低,以及背散射(ΔBS)曲线底部和顶部的轻微变化;微波预处理使黑芝麻乳静态体系的弹性行为增强、流动性减弱,表观黏度逐渐降低,动态黏弹性增加,其中微波预处理9 min时最为明显;微波预处理使黑芝麻乳中脂滴数量和粒径明显增加,连续相中贮藏蛋白构成的多孔片层结构减少,提示优先参与乳体系中脂滴重构。因此,适宜时长微波预处理能够改善黑芝麻物性特征和全籽乳稳定性,拓宽黑芝麻的应用场景。

不同乳源乳脂肪球的体外消化特性

基于模拟婴幼儿胃肠道消化,采用粒径分布、Zeta电势和激光共聚焦扫描电镜观察不同乳源(牛、羊、驼)乳脂肪球(MFG)在消化各阶段物理特性的差异,采用气相色谱-质谱联用及滴定法,探究在不同消化阶段游离脂肪酸及脂解速率的变化,完善脂质消化的变化规律。结果表明,不同乳源MFG的颗粒粒径随消化时间的延长,均呈减小的趋势,与激光共聚焦显微镜染色后观察结果一致。在肠消化末端,驼乳MFG的平均粒径为(0.46±0.07)μm,显著低于牛乳MFG的粒径(P<0.05)。动态光散射电位仪测得电势绝对值显示,所有乳源MFG进胃肠消化后均表现出强负电性,其中肠消化末端的电位绝对值由大至小排序为羊乳>牛乳>驼乳。不同乳源MFG在肠道消化期间的脂解速率无明显差异,而驼乳MFG相较于其它两种乳源在不同消化阶段,棕榈油酸(C16∶0)的含量显著更高(P<0.05),长链脂肪酸比例更低。研究结果为驼乳产品的加工以及新型配方奶粉的制备提供新思路。

三组多菌群益生菌发酵羊乳酸乳的特性分析

该研究分别以嗜热链球菌与5株乳杆菌组合(SN_4)、嗜热链球菌与保加利亚乳杆菌组合(SN_2)、5株乳杆菌组合(SN_3)三组益生菌组合对羊乳进行发酵,对发酵过程中(0~12 h)活菌数、pH值、酸度、持水力及凝乳点的质构特性、流变特性、菌群结构、功能性差异代谢物等进行分析研究。结果显示,SN_4、SN_2、SN_3的凝乳时间依次为4.70、5.60、10.60 h;活菌数均可达到109 CFU/mL以上;发酵至凝乳点,链球菌属和乳杆菌属均被检出;SN_4组合发酵酸乳的持水力、质构特性和流变特性等均表现最优,SN_2次之;在P<0.05水平上,SN_4与SN_2相比,18种肽类、2种糖类、7种有机酸差异代谢物中分别有13种、2种和2种上调;SN_4与SN_3相比,18种肽类、7种糖类、6种有机酸差异代谢物中分别有5种、4种和6种上调;SN_3 VS SN_2、SN_4 VS SN_2、SN_4 VS SN_3差异代谢物通路分别涉及7条、5条、4条。研究结果表明,SN_4发酵酸乳特性均优于SN_2、SN_3。研究结果可为进一步研制感官优良、功能性强的多菌群发酵酸乳提供理论依据与技术支撑。

低乳糖牛乳粉品质分析及蛋白特性研究

为获得品质优良的低乳糖牛乳粉,该试验以生牛乳为原料,分别使用3种不同乳糖酶水解牛乳,对水解后的牛乳进行喷雾干燥得到了低乳糖牛乳粉-乳糖酶A(low lactose milk powder-enzyme A,LLMP-EA)、低乳糖牛乳粉-乳糖酶B(low lactose milk powder-enzyme B,LLMP-EB)、低乳糖牛乳粉-乳糖酶C(low lactose milk powder-enzyme c,LLMP-EC),测定其理化指标和游离巯基等蛋白特性。结果表明,LLMP-EA、LLMP-EB和LLMP-EC的外观及组织状态相近、色泽偏白,LLMP-EA的水分活度比LLMP-EB、LLMP-EC分别低6.29%、4.07%(P<0.05);LLMP-EA的水分含量比LLMP-EB、LLMP-EC分别低6.13%、3.32%(P<0.05);LLMP-EA多分散性指数(polydispersity index,PDI)值为0.13,LLMP-EA、LLMP-EB和LLMP-EC的Zeta电位无显著性差异(P>0.05);通过扫描电镜(scanning electron microscope,SEM)观察发现,LLMP-EA乳粉颗粒较为饱满、表面光滑、有轻微凹陷、颗粒聚集程度较低;LLMP-EA的游离巯基含量比LLMP-EB、LLMP-EC分别低19.90%、12.15%(P<0.05),而LLMP-EA表面疏水性比LLMP-EB低12.29%(P<0.05);LLMP-EA的α-螺旋结构分别比LLMP-EB、LLMP-EC高1.35%、1.94%(P<0.05)。因此,LLMP-EA的水分含量和水分活度低、PDI值仅为0.13,品质最佳;游离巯基含量和溴酚蓝结合量低、α-螺旋含量高,蛋白特性较好。