The effect of long-term frozen storage on the quality of frozen and thawed mashed potatoes with added cryoprotectant mixtures

Cryoprotectant mixtures were added to frozen/thawed (F/T) mashed potatoes in the form of amidated low-methoxyl (ALM) pectin and xanthan gum (XG), kappa-carrageenan (κ-C) and XG and sodium caseinate (SC) and XG, and the effect of frozen storage was examined. F/T mashed potatoes without added biopolymers had higher storage modulus G ' after freezing and frozen storage, associated with sponge formation due to amylose retrogradation. Oscillatory measurements indicated weakening of the structure of mashed potatoes without biopolymers and with added κ-C/XG and SC/XG mixtures at the end of storage due to ice recrystallisation, whereas the structure of samples with added ALM/XG mixtures was reinforced by increasing time in storage. Mashed potatoes with added mixtures exhibited water-holding capacity for 1 year. Samples with added κ-C/XG mixtures were more structured, although when both κ-C/XG and SC/XG mixtures were included in mashed potato, very acceptable sensory quality was maintained in usual frozen storage conditions.     

Yield Stress and Time-dependent Rheological Properties of Mango Pulp

Mango pulp was tested for time-independent and time-dependent flow properties using a coaxial cylinder rheometer. Mango pulp is a pseudoplastic liquid with yield stress, and exhibits thixotropic properties. The yield stress calculated using the Casson or Bingham plastic models, had markedly higher values than those determined by stress relaxation, controlled stress experiments, or from stress-strain plots. The yield stress of mango pulp tested in this experiment was sensitive to temperature and decreased rapidly as temperature increased. The time-dependent model of Weltman was found to be most applicable (|r| 0.991, p 0.01) for mango pulp.     

芒果香精的调配

分析了芒果易挥发的香气化学成分,通过青香韵,果汁香韵,酸香香韵,木香香韵,焦甜香韵,果甜香韵,牛奶香韵,玫瑰甜香韵,热带水果香韵对芒果香气进行阐述。经过精心设计的3组调香配方实验,表明2#芒果香精配方的是与成熟的芒果较为接近,它具有浓郁的,新鲜的,多汁的,甜中带青的果香,带有热带水果的特征香气,且带有浆果果香气,体香厚实,留香长,香精整体协调自然,与目标产品接近。     

1-MCP及物流方式对芒果货架品质及软化酶活性的影响

为了探讨1-甲基环丙烯（1-methylcyclopropene,1-MCP）对芒果经不同物流运输后货架品质及软化酶活性的影响,以“红玉”芒果为试材,经1-MCP处理后进行运输包装,选用航空托运和快递空运两种物流方式从海南运至天津,测定不同处理芒果在常温货架期感官、质地、营养、生理及相关酶活性的变化规律。结果表明,经不同物流运输后的芒果在常温货架（25～28 ℃）条件下,1 μL/L 1-MCP处理能够较好地保持芒果的货架品质,抑制转黄指数和软化衰老程度的下降,延缓呼吸强度、乙烯释放量及多聚半乳糖醛酸酶（PG）和纤维素酶（CX）活性的上升,维持果实较好的可溶性固形物、可滴定酸及VC含量。不同物流运输处理比较分析得出,航空托运优于快递空运,其中果肉平均硬度、可溶性固形物、VC含量、乙烯释放量及CX活性等指标存在显著性差异。结果说明1-MCP结合航空托运是芒果电商的最佳采后处理方式。     

不同渗糖方式对芒果果脯品质及组织细胞的影响

本文以芒果残次果为原料,在常温条件下,研究了超声波、微波和真空三种渗糖处理方式对芒果果脯色泽、质地、复水率、总糖含量以及对芒果组织细胞的影响。结果表明;真空渗糖方式对芒果色泽和质构影响最明显,得到的芒果果脯色泽红度值降低,色泽、硬度、胶着性和咀嚼性与常压对照存在显著性差异(P0.05);而超声波和微波渗糖方式对芒果果脯色泽和质构影响较小;超声波渗糖方式最有利于促进芒果果脯的渗糖,得到的果脯总糖含量最高;三种渗糖方式与常压对照组相比降低了芒果果脯复水率,但影响较小,复水150 min时三种渗糖方式下芒果果脯复水率在189.27%~191.10%之间;通过显微镜观察渗糖后芒果组织切片,发现超声波渗糖方式能明显降低渗糖对芒果组织细胞结构的破坏作用。     

Characterization of the Interactions between Cereal Flour and “Nata Puree” in Batter

This study aimed to characterize the interactions between cereal flour (rice, wheat, and barley) and “nata puree” (NP), a disintegrated bacterial cellulose (BC) in the presence of a water-soluble polysaccharide, with powder-dispersion activity. Pasting properties of cereal flour with additives were analyzed using a Rapid Visco Analyzer, and disintegrated BC in water (BCW), three water-soluble polysaccharides: (1,3)(1,4)-β-glucan, tamarind seed gum, and birchwood xylan, and the corresponding NPs were used as additives. For rice flour, additional BCW or NPs increased the initial and the peak viscosity. The addition of water-soluble polysaccharides produced the opposite trend: viscosity increased from the peak time to the end of measurements. For wheat flour, the addition of BCW or NP delayed the peak time and increased peak viscosity; the increase was maintained till the end of measurements. For barley flour, the additional BCW or NP caused a higher gelatinization rate and increased viscosity at the starch-retrogradation stage. Next, static gelatinization of a rice flour suspension in NP was successfully accomplished before placing it in a vessel; NP concentration in the gel significantly affected the firmness. Thus, the dynamic and unique interactions between various cereal flours and cell-wall polysaccharides in NPs can increase the flours'' potential; static gelatinization of cereal flour with NP could expand flours'' application range in both current and next-generation cooking.     

一株芒果炭疽病拮抗菌抑菌活性的研究及其鉴定

从芒果表皮分离得到29株内生细菌,对峙培养法发现菌株B2-1对芒果炭疽病菌丝的生长具有较强的抑制作用。通过离体实验和活体实验对拮抗菌株B2-1抑菌活性进行了研究,离体实验结果表明,B2-1的发酵滤液、挥发性代谢产物以及非挥发性代谢产物都对芒果炭疽病菌丝的生长有很强的抑制作用,其中B2-1发酵液的非挥发性代谢产物对芒果炭疽病菌丝生长的抑制率达到了99.86%,抑菌效果显著。活体实验结果表明,B2-1的菌悬液和发酵液与对照相比显著降低了芒果炭疽病的发病率,提高了芒果的可食用果率。进一步对菌株B2-1进行鉴定,综合形态学观察和生理生化特征检测以及16S rDNA序列分析,B2-1菌株被鉴定为枯草芽孢杆菌。      

Changes in carotenoids during processing and storage of pumpkin puree

Changes in the contents of carotenoids and their true retentions (% TR) during the production of puree of Cucurbita moschata ‘Menina Brasileira’ and of Cucurbita maxima ‘Exposição’ pumpkins and the stability of such compounds during 180 days of storage were monitored by liquid chromatography coupled with a photodiode array detector. Cooking caused higher losses than commercial sterilisation. High losses of xanthophylls such as lutein and violaxanthin were noted during processing and storage of pumpkin puree. Such losses show the low stability of these compounds. The major carotenoids, pro-vitamin A carotenes, namely, α-carotene and all-trans-β-carotene for C. moschata ‘Menina Brasileira’ and all-trans-β-carotene for C. maxima ‘Exposição’ obtained high retentions (>75%) after processing. A slight degree of isomerisation of β-carotene was noted in the puree samples, but with low concentrations of cis-isomers. Storage for 180 days did not significantly affect (P ? 0.05) the concentrations of these carotenoids.     

基于单片机的芒果智能分拣系统优化设计

通过对芒果自动分拣设备功能需求、工序流程等方面的分析,设计了芒果自动分拣设备,建立了集传感器-单片机-驱动电机为一体的测控系统,实现了机电一体化技术原理及方法在小型农机自动化设备上的优化设计.针对芒果分拣设备智能化、便携化、成本低等要求,优化机械结构设计,并对进行测试实验,达到较为理想的预期效果.     

芒果原浆、芒果糖浆的研制

本文研究了以芒果为原料加工成芒果原浆、芒果糖浆的适宜加工品种、加工工艺和配方、色泽风味保持、产品评价,提出了适宜加工品种、合理工艺和操作要点、产品配方和质量标准。是一项适宜芒果产地的芒果加工技术。