Anthocyanin-fortified konjac glucomannan/sodium alginate composite edible boba: characteristics of texture,microstructure, in vitro release behaviour and antioxidant capacity

Konjac glucomannan/sodium alginate composite edible boba (KGM/SA-boba) with good taste is very popular in China, and it is an outstanding carrier for health potential ingredients. In this work, KGM/SA-boba were fortified with 0.25, 0.50, 0.75 and 1.00% purple sweet potato anthocyanin (PSPA), then characterised by the water distribution, texture, microstructure, in vitro release property of PSPA and antioxidant capacity. LF-NMR analysis demonstrated that the free water of KGM/SA-boba could transfer to tightly bound water with the addition of PSPA that made it with better water-binding ability, higher springiness and lower hardness. And the results of SEM and rheology showed that PSPA could stabilise the microstructure of KGM/SA-boba by forming more amorphous regions and hydrogen bonds proved by the results of DSC and FT-IR. Furthermore, 50% of PSPA in PSPA-fortified KGM/SA-boba can be released at the first hour in a simulated gastrointestinal environment. And the scavenging capacity of DPPH and ABTS of the PSPA-fortified KGM/SA-boba after digestion was higher than that of PSPA alone. Generally, PSPA could improve the texture while KGM/SA-boba in turn would make PSPA more stable in the gastrointestinal digestive system.     

Improvement of thermal,microwave and ultrasonication pretreatment on the production of antioxidant peptides from sweet potato protein via in vitro gastrointestinal digestion

Effects of thermal (boiling, steaming and autoclaving), microwave and ultrasonication pretreatments on the production of sweet potato protein hydrolysates (SPPH) through in vitro gastrointestinal digestion (GID) were investigated. All pretreatments significantly increased the degree of hydrolysis (DH), antioxidant activities and molecular weight (MW) <3 kDa peptide fractions contents of SPPH in the order of autoclaving > microwave, steaming > boiling > ultrasonication (P < 0.05). Correlation analysis between peptides content and antioxidant activity suggested that antioxidant activity of SPPH mainly attributed to MW <3 kDa peptides. Diverse peptides ranged from 487.24 to 1477.74 Da with 7–13 amino acids were identified in the MW <3 kDa peptides fraction with autoclaving pretreatment and matched sporamins A, A precursor and B sequences from LC–QTOF–MS/MS analysis. Conformational structures of nine peptides were predicted with well-known antioxidant amino acids. There is a high potential for SPPH used as a functional supplement in food system.     

1-甲基环丙烯结合不同保鲜袋对叶用甘薯茎尖冷藏保鲜效果的影响

目的探究1-甲基环丙烯(1-methylcyclopropylene,1-MCP)结合不同保鲜袋对叶用甘薯茎尖贮藏品质的影响,筛选最适的保鲜方式。方法以叶用甘薯茎尖为材料,经0.91μL/L1-MCP处理24h后结合聚乙烯(PE)或微孔膜(WK)保鲜袋包装,在5℃下进行贮藏,分别于0、3、6、9、12 d时对其失重率、色差、黄化率、呼吸强度、乙烯释放量、多酚氧化酶活性等指标进行测定。结果贮藏12 d后, 1-MCP+PE, 1-MCP+WK处理组的失重率分别为3.43%,2.72%,显著低于未经1-MCP处理组(P0.05),说明1-MCP处理能够有效抑制叶用甘薯茎尖失水; 1-MCP+WK处理下的L值为33.9,高于其余3种处理,表明该处理能够更好的保持叶用甘薯茎尖的亮度和新鲜感。此外,1-MCP结合保鲜袋处理能够减弱呼吸作用,降低乙烯释放量及多酚氧化酶活性。结论1-MCP处理并结合PE膜或者微孔膜包装对叶用甘薯茎尖具有良好的保鲜效果,可以有效延长其贮藏期。     

薯类粉条中与淀粉相关的结构性质研究

为了解薯类淀粉粉条结构特点,选取3种木薯淀粉(SC9、SC205、LMC),3种淮山淀粉(GY2、SFY、MPY)和1种红薯淀粉(XSSP)制成的粉条为研究对象,对其色泽、微观样貌、结晶结构进行测定和比较。结果表明,各粉条的色泽、微观样貌、结晶结构差异显著。星树红薯粉条色泽最好,而双峰淮山粉条色泽较暗。淮山粉条和红薯粉条存在部分还未完全糊化的淀粉颗粒,呈现出清晰的团粒结构,木薯粉条的糊化程度最高,淀粉的团粒结构已基本消失,SC9木薯粉条可以看到均匀完整的网络结构。粉条的结晶结构均遭到破坏,不同品种薯类粉条的有序结构与无序结构比例有明显差异。     

辽宁省主栽品种马铃薯块茎和马铃薯全粉的品质分析

以辽宁省主栽的11个品种马铃薯块茎为原料,采用捣碎制泥工艺生产马铃薯颗粒全粉,测定其原料品质指标(总淀粉、蛋白质、还原糖、脂肪、粗纤维和氨基酸)和颗粒全粉功能性指标(碘蓝值、透光率、冻融稳定性、持水和持油性)。结果表明:11个马铃薯品种的淀粉含量为67.9%~73.4%,其中大西洋、919淀粉含量高,早大白和克23淀粉含量低;蛋白质含量差异较大,其中富金、尤金蛋白质含量高,中5蛋白质含量最低;还原糖含量差异也较大,BQ25和大西洋含量较低,克23还原糖含量较高;脂肪含量差异不大;大西洋粗纤维含量较低,克23粗纤维含量较高。异亮氨基酸、苯丙氨基酸+酪氨酸含量11个品种均高于世界卫生组织(WHO)的“必需氨基酸模式标准”,相对其他氨基酸,33、大西洋、夏波蒂和中5的氨基酸含量较高。11种马铃薯全粉的游离淀粉率差异不大。但是透光率差异很大,919的透光率最大,BQ25和大西洋的透光率较小。富金、克23和33的析水率较高,BQ25和大西洋析水率低。11种马铃薯全粉的持水能力为7.3~8.1 g/mL,持油能力为7.6~8.6 g/mL。     

基于百度学术搜索引擎的马铃薯糖苷生物碱研究态势分析

在茄科(Solonum)和一些百合科(Liliaceae)植物中存在着一类天然次生代谢产物糖苷生物碱(steroidal glycoalkaloids, SGAs),对于植物体来说,该物质具有抗拒病原微生物侵袭、昆虫采食以及化感效应等,但对于人畜来说,虽然该物质具有抑制癌细胞增长和调节风味等作用,但在马铃薯(SolonumtuberosumL.)块茎中含量较高时可导致人畜中毒、甚至死亡。研究分析近年来的马铃薯SGAs研究态势,结果表明,相关发文量总体呈逐渐增加的趋势,关于马铃薯SGAs的研究已渗透到许多学科,并与之形成了多个交叉学科,通过统计分析,总结出在该领域核心的相关研究人员和研究机构。因此,掌握马铃薯SGAs研究态势,对研究马铃薯SGAs以及其在马铃薯块及其制品中食用安全性具有重要意义。     

可溶态和膜结合态马铃薯多酚氧化酶的性质对比

以大西洋马铃薯为原料,制备可溶态(s PPO)和膜结合态(mPPO)多酚氧化酶,并对两种粗酶液的酶学性质进行研究。结果表明,s PPO最适反应温度为35℃,最适p H值为7,mPPO最适反应温度为30℃,最适pH值为7。以焦性没食子酸、邻苯二酚为底物时,sPPO的米氏常数(K_m)分别为10.04 mmol/L和24.00 mmol/L,最大反应速度(V_(max))值分别为443 U/(mL·min)和965U/(m L·min),mPPO的米氏常数(K_m)分别为4.98 mmol/L和48.04 mmol/L,最大反应速度(V_(max))值分别为299 U/(mL·min)和912U/(m L·min),且对焦性没食子酸的催化效果优于邻苯二酚。6种抑制剂对比发现,Na_2SO_3对sPPO活性的抑制效果最好,Vc对mPPO活性的抑制效果最好。sPPO和mPPO的酶学特性有一定的差异,对马铃薯制品加工过程中酶促褐变的控制具有指导意义。     

Physicochemical characteristics,antioxidant capacity and thermodynamic properties of purple-fleshed potatos dried by radio frequency energy

Abstract

The impacts of using radio frequency (RF) energy to dry purple-fleshed potatoes were investigated and compared to infrared radiation (IR) and microwave (MW) drying techniques. The gelatinization rate, color, flavor, morphological, and structural characteristics, thermodynamic properties, as well as antioxidant capacity were examined. The results indicated that the drying time of RF (70?min) and MW (21?min) were shorter than IR (105?min). The gelatinization ratio of MW, RF, and IR were 94.4?±?2.0, 88.3?±?1.4, and 64.5?±?1.1%, respectively. The degree of crystallization of purple-fleshed potato powder decreased with all three drying methods. RF-dried potatoes were able to retain higher polyphenols (loss rate: 4.3%), total anthocyanin (3.7%), and total flavonoid content (35.1%), whereas IR showed the lowest retention. The content of polyphenols also decreased significantly. Furthermore, after RF heating, the scavenging of free radicals was higher compared to MW and IR.     

CO2辅助挤压对马铃薯渣可溶性膳食纤维的影响

以马铃薯渣为原料,研究CO2辅助挤压各工艺条件对马铃薯渣可溶性膳食纤维的影响。结合马铃薯渣颜色、持水力、持油力和膨胀力的变化,得出CO2辅助挤压最佳工艺参数为:CO2发生剂柠檬酸与碳酸氢钠添加质量比为1∶1、添加量30%(质量分数)、挤压温度185℃、物料含水量25%(质量分数)、螺杆转速170 r/min。在此工艺条件下,挤压所得马铃薯渣可溶性膳食纤维含量较高,色泽较好,水合特性得到较好地保持,可为马铃薯渣膳食纤维的改性提供参考。