基于质地多面分析法对不同苹果品种果肉质构特性的分析

为了细致研究"华红"苹果贮藏期间果肉质地变化和不同苹果品种质构特性差异,本实验以套袋和未套袋"华红"苹果为试材,应用质地多面分析法定期测定贮藏期间果肉质地参数;以及以不同熟期"华红"、"华苹"、"寒富"、"红星"、"嘎拉"、"津轻"为试材,比较不同苹果品种果肉质地品质差异,同时分析各质地参数之间相关性。"华红"套袋和未套袋果肉质地参数在常温贮藏过程中变化趋势基本一致,且未套袋果肉的各项质地参数稍高于套袋的。硬度呈下降趋势,在黏附性、内聚性、弹性、咀嚼性、回复性方面,贮藏0 d的果实与48 d相比稍有升高。"华红"果肉贮藏期间质地参数变化相关性和6个苹果品种之间质地参数相关性有相似处,内聚性与弹性、回复性、咀嚼性都呈正相关,弹性与回复性、咀嚼性都呈较好地正相关,回复性与咀嚼性呈较好的正相关。不同的是,"华红"果肉硬度与黏附性、内聚性呈负相关,而不同品种之间果肉硬度与内聚性、弹性、回复性、咀嚼性呈高度正相关。不同品种之间各质地参数也进行了量化比较。综上说明本实验选用的P5探头测定的果肉内聚性、弹性、回复性、咀嚼性能反映"华红"果肉质地变化规律,适用于苹果果肉质地品质的客观评价。硬度、内聚性、弹性、回复性、咀嚼性质地参数中的一项或多项可以作为评价"华红"果肉质地和比较这6个苹果品种果肉质地差异性的重要参数。     

EFFECT OF DIFFERENT COATING TREATMENTS ON THE QUALITY OF MANGO FRUIT

Eight coating formulations were evaluated for beneficial effects on the shelf‐life of mangoes (cvs. Kent, Tommy Atkins, and Lirfa) harvested at different maturity stages. Four coatings were then selected for further study under various conditions of storage including ambient (19–22C and56–60% RH) and simulated commercial (12C and 80% RH) storage. The four coating formulations contained carnauba wax, shellac, zein, and/or cellulose derivatives. All coatings reduced the respiratory rate, the development of external and internal color, and all but carnauba wax retarded the loss of firmness. Changes in acids were also delayed in all coated mangoes. Based on these parameters, fruit maturation was estimated to have been delayed by a few days compared with uncoated fruit. Shellac and cellulose‐based coatings, however, caused elevated levels of ethanol, although this did not lead to significant flavor differences from the control (uncoated fruit) in sensory tests. Only the carnauba wax coating was an effective water loss barrier under conditions of high RH.     

Characterization of Hazelnut Oil Oleogels Prepared with Sunflower and Carnauba Waxes

In this study, hazelnut oil oleogels prepared with sunflower wax and carnauba wax were analyzed and compared with a commercial shortening. Oil binding capacities of sunflower wax oleogels were higher than 99%, while carnauba wax had a maximum value of 97.6% for 10% addition level. At 3% addition level of carnauba wax, no gel developed. The crystal formation time of sunflower wax was shorter. Although the highest (8.5%) solid fat content was observed in the 10% carnauba wax containing oleogel (HC10) sample, it was 30.4% in the commercial shortening sample at 20°C. The peak melting temperature of commercial shortening was 52.3°C, and among all organogels, sunflower wax oleogel at 3% addition level had the closest value (58.4°C). The melting enthalpies of the oleogels ranged from 4.3 to 20.3 J/g, while it was 10.9 J/g for the commercial shortening sample. The firmness and stickiness values in the oleogel samples were lower than that of commercial shortening sample. On the other hand, there was no significant change of firmness and stickiness during storage, indicating good stability (p ≤ 0.001). Especially the sunflower wax oleogels were very homogenous and smooth in structure. The polarized light microscopy pictures revealed needle-like crystals for sunflower wax and aggregate-like crystals for carnauba wax oleogels. The x-ray diffraction measurements of the crystals showed the β´ types of the polymorphic structures. Furthermore, the oleogels were very stable against oxidation during the storage period. Hazelnut oil organogels prepared with sunflower wax can be good source material for shortening or margarine-like products.     

Effect of Thermal Treatment on Selected Cereals and Millets Flour Doughs and Their Baking Quality

Selected cereals (rice and sorghum) and millets (finger millet and pearl millet) were steamed for 20 min at ambient pressure. The rheological properties of doughs, made from these steamed as well raw grain flours, were characterized in addition to examining their baking quality. The two-cycle compression test was employed and instrumental values were correlated with sensory attributes (color, aroma, taste, stickiness, chewiness, tearing strength, cohesiveness, and rollability) using principal component analysis (PCA). Rice doughs made from both raw as well as thermally treated flour imparted maximum hardness (96.6–99.3 N) and least cohesiveness (0.05–0.09) with highest stickiness values (105–110°) among all the dough samples at the same moisture content. Pearl millet and raw sorghum flour doughs possessed the least instrumental hardness, adhesiveness, and stickiness and were the easiest to flatten. The PCA biplot showed that sensory and instrumental cohesiveness formed a cluster on the left side on the x axis while shear force, and sensory attributes like tearing strength, chewiness, stickiness, and rollability formed another cluster on the other side of the axis. Raw rice and finger millet doughs were associated with the high extent of instrumental and sensory stickiness. Thermally treated pearl millet and sorghum doughs were the best followed by treated rice and finger millet samples to give the desirable dough characteristics, and were quite close to wheat chapathi in texture.     

增城丝苗米米饭理化性质与质构特性的相关性分析

选用7份增城丝苗米的原料大米,研究米饭的质构特性,并分析其与大米的热特性、糊化特性和理化指标之间的相关性。结果表明,增城丝苗米原料大米的硬度、粘性的差别较大,而凝聚性、胶粘性、咀嚼性和回复性均较接近。大米直链淀粉含量与米饭质构特性呈显著相关,米饭硬度、粘性与大米淀粉的糊化起始温度呈正相关,与热焓值呈负相关。米饭的硬度、粘性、凝聚性、胶粘性、咀嚼性和回复性与大米淀粉糊化的最终粘度、崩解值呈负相关,与消减值呈正相关,粘性与回生值呈负相关。因此,开发大米配方时, 将直链淀粉含量检测与大米的糊化特性、米饭硬度和粘性测试分析相结合,对于提高大米配方的品质稳定具有重要意义。     

水溶性壳聚糖对梅鱼鱼丸贮藏过程中凝胶特性的影响

以梅鱼鱼丸为材料,通过色差分析、TPA质构分析和环境扫描电镜扫描观察梅鱼鱼丸凝胶的微观结构,评价了在0℃贮藏条件下水溶性壳聚糖对梅鱼鱼丸凝胶特性的影响。实验结果表明:一定添加浓度范围内(添加量0.5%～1.5%)水溶性壳聚糖不会影响鱼丸的色泽,同时可显著提高梅鱼鱼丸的凝胶能力,提高硬度、弹力和咀嚼性,保持弹性、黏着性和凝聚性。且在此范围内随着水溶性壳聚糖浓度的增加,凝胶强度也随之增加。环境扫描电镜观察结果显示,水溶性壳聚糖能使鱼丸的凝胶更加致密,减少鱼丸凝胶的孔洞和空隙,从而提高梅鱼鱼丸的感官品质。     

大米垩白度与米饭蒸煮品质的相关性研究

本文研究了五种垩白度不同的原料米饭在高压蒸煮工艺条件下的蒸煮品质,并对垩白度与多种蒸煮品质指标进行了相关性分析;同时为了满足少量米饭品质测定需要设计了微波蒸煮米饭的工艺条件,研究微波蒸煮工艺条件下不同垩白面积对米饭糊化度的影响。研究发现:大米蒸煮后米饭的膨胀率和吸水率与原料米的垩白度呈负相关,但是均未达到显著性水平;质构特性与垩白度的相关性分析表明垩白度主要影响米饭的硬度,对米饭粘度、粘聚性、回复性、弹性、胶粘性和咀嚼性有一定影响,但影响并不显著;原料米的垩白度与米饭形态呈极显著负相关;与口感呈显著负相关;与色泽、滋味、香气均有一定相关性,但均未达到显著水平;微波蒸煮试验显示全垩白米样糊化速度较无垩白米样在3~15 min阶段都要快,且最终糊化度值全垩白米样比无垩白米样大。     

Batter rheology and bread texture of sorghum‐based gluten‐free formulations modified with native or pregelatinised cassava starch and α‐amylase

The influence of α‐amylase (0–0.3 U g^?1) on the crumb properties of gluten‐free sorghum batter and bread, respectively, was investigated. The formulations were modified using native or pregelatinised cassava starch (i.e. batter A – 17% pregelatinised starch, 83% sorghum, 100% water fwb; batter B – 17% native starch, 83% sorghum, 100% water fwb; and batter C – 30% native starch, 70% sorghum, 80% water fwb). The batters had solid viscoelastic character with the storage modulus predominant over the loss modulus. Storage moduli of batter A decreased with increasing angular frequency, whereas the moduli of batters B and C were independent from the angular frequency. Increasing enzyme concentration did not affect the loss factors of the batters. Batters’ resistance to deformation, from highest to lowest, followed the order C > A > B. Increasing enzyme concentration decreased crumb firmness, cohesiveness, springiness, resilience and chewiness but increased adhesiveness. Overall, breads containing native starch had better crumb properties (i.e. springier and less firm, chewy and adhesive) than breads containing pregelatinised starch.     

冰温和自发气调袋贮藏对冬枣质构及生理特性的影响

本文以成熟冬枣为试材,选取冰温贮藏和自发气调袋贮藏两种方式,测定贮藏过程中的硬度、弹性、粘性、内聚性和咀嚼性等质构特性,并进行贮藏相关生理指标的测定。结果表明,冰温贮藏可以延缓冬枣果实的硬度、粘性和弹性的下降,延缓冬枣质构的衰变,同时降低可溶性果胶含量,从而抑制冬枣果实的软化。自发气调袋处理的果实其质构特性明显优于对照果实,且冬枣果实在贮藏过程中失重率明显低于对照和冰温贮藏的冬枣果实。对照果实,冰温处理和自发气调保鲜袋处理的冬枣果实贮藏至20 d时,失重率分别为12.02%,10.25%和1.17%。自发气调保鲜袋处理可以延缓冬枣果实的Vc含量下降,保持果实较高的营养品质。冰温贮藏能够延缓果皮花青苷的形成,贮藏20 d后红色果皮部分不到1/3,而自发气调保鲜袋处理的果实花青苷会正常合成。自发气调袋处理的效果优于冰温贮藏。     

米糠蜡对大豆油凝胶特性的影响研究

在大豆油中添加米糠蜡以制备凝胶油。考察了米糠蜡添加量和冷却温度对凝胶油的影响。结果表明:米糠蜡添加量为8%时,在常温下能形成凝胶油且口感较好,具有一定的塑性。随着米糠蜡添加量的增加,米糠蜡凝胶油在硬度增加的过程中,胶着度下降,弹性和咀嚼度也随之下降,回复性基本不变。此外,在弹性以及黏聚性方面,米糠蜡凝胶油和人造黄油接近。随着米糠蜡添加量的增加,凝胶油的熔融温度和结晶温度升高。     

Influence of wax type on characteristics of oleogels from camellia oil and medium chain triglycerides

Camellia oil (CO) and medium chain triglycerides (MCTs), characterised by different carbon chain lengths, were gelled using beeswax (BW), candelilla wax (CLW) and carnauba wax (CRW). Critical concentrations, oil-binding capacity (OBC), textural parameters, thermal properties, microscopic properties and infrared spectra were used to evaluate their differences. The carbon chain length of oil sources showed different results for the critical concentration of the three wax-based gel oils at 25 °C, and the oleogel of MCT and CLW exhibited a minimum value (1%). The oleogels formed from CO and waxes with wax esters as the main components (BW and CRW) exhibit significantly lower OBC and textural value than the oleogels made from MCT with BW and CRW. Meanwhile, this is corroborated with the thermal behaviour and crystal morphology, and distribution of the oleogels. However, no differences in crystal types and generation of new functional groups were observed by X-ray diffraction and Fourier-transform infrared spectrometer, suggesting that the differences in the properties of wax-based oleogels with different carbon chain lengths are attributed to the interactions between the waxes and the oil sources (physical interaction).     

肉桂精油/羟丙基-β-环糊精包合物对κ-卡拉胶质构和流变特性的影响

研究了不同肉桂精油/羟丙基-β-环糊精(hydroxypropyl-β-cyclodextrin,HPBCD)包合物添加量对κ-卡拉胶凝胶质构特性、熔凝胶温度和储能模量的影响。结果表明,κ-卡拉胶凝胶的硬度、胶黏性、咀嚼性在HPBCD包合物的添加量为3%时达到最大值,但肉桂精油/HPBCD包合物对κ-卡拉胶凝胶的弹性和内聚性影响不明显。κ-卡拉胶的凝胶、熔胶温度随包合物添加量的增加分别升高了1.65和2.1℃。κ-卡拉胶的储能模量(storage modulus,G')随包合物添加量的增加先升高后降低,且在添加量为3%时G'达到最大值。本研究结果可为环糊精包合物对κ-卡拉胶凝胶性能的影响提供理论参考。     

Modification of gluten-free sorghum batter and bread using maize, potato, cassava or rice starch

Gluten-free sorghum bread was made from cassava, maize, potato or rice starch and sorghum in the ratios 10:90, 20:80, 30:70, 40:60 and 50:50. The other baking ingredients, on flour-weight-basis, were water (100%), sugar (6.7%), egg white powder (6%), fat (2%), salt (1.7%) and yeast (1.5%). Increasing starch content changed the batters’ consistencies from soft doughs to thin pourable batters. Increasing starch content decreased crumb firmness and chewiness, and increased cohesiveness, springiness and resilience of all breads. Cassava-sorghum and rice-sorghum breads had better crumb properties than maize-sorghum or potato-sorghum breads. Although the crumb properties of all breads declined (i.e. firmness and chewiness increased; cohesiveness, resilience and springiness decreased) on storage, the formulation containing 50% cassava starch retained the best overall texture.     

Texture Profile of Ripening Pears

SUMMARY— Pears of the Ovid variety were harvested at the normal stage of maturity, and ripened in a 70°F storage room. Samples of the fruit were taken out at regular intervals for texture measurements which consisted of the Magness-Taylor pressure test and a modified General Foods Texture Profile. The adhesiveness of the pears was zero. The viscosity of the whole fruit could not be measured. All other parameters of the G. F. Texture Profile (hardness, cohesiveness, elasticity, brittleness, chewiness, and gumminess) decreased during ripening at approximately the same rate as the pressure test. It is suggested that this characteristic of ripening pears is responsible for the success of a simple single measurement (the puncture test) for measuring the complex phenomenon that is called "textural quality" of pears.     

甘南牦牛肉质构特性分析

以甘南牦牛肉为材料,采用质地多面剖析法研究了牦牛肉成熟过程中质构特性的变化,同时,分析了牦牛肉质构各指标间的相关性.结果表明:经过7d的成熟,牦牛肉的质构指标如硬度、内聚性、弹性、咀嚼性、黏附性总体均呈下降的趋势,同时,牦牛肉的硬度与咀嚼性、内聚性呈现极显著的正相关(P＜0.01),咀嚼性与硬度、内聚性也呈现极显著的正相关(P＜0.01).     

SENSORY AND INSTRUMENTAL TEXTURE ANALYSIS OF CASSAVA (MANIHOT ESCULENTA, CRANTZ) ROOTS

Two cassava varieties, at three harvesting ages, 6, 12 and 24 months, were analyzed for sensory flavor and texture development. Maximum shear force, Texture Profile Analysis (TPA) and water absorption during cooking were determined at various sampling times. Changes during cooking were described by pseudo‐zero order models for water absorption, flavor and texture development for the fast cooking samples. The 24‐month‐old roots had higher variability and never reached optimum texture or flavor development. Significant pseudo first order models could represent hardness, cohesiveness and chewiness of the TPA, while springiness and adhesiveness varied in a non‐linear fashion. Maximum shear force was 111 N for raw samples and 8.1 N for samples that cooked in less than 25 min. Samples that required longer cook time had on the average a maximum shear force of 19 N.     

Physicochemical properties and oxidative stability of oleogels made of carnauba wax with canola oil or beeswax with grapeseed oil

Two types of oleogels—made of carnauba wax with canola oil or beeswax with grapeseed oil—were prepared at concentrations from 0 to 15% (w/w) of wax. Physical characterization was done and oxidative stability of the oleogels were evaluated. As the proportion of wax increased from 5 to 15%, the enthalpy of crystallization and melting increased in both oleogels. The carnauba wax-based oleogel (CWO) required greater enthalpy than the beeswax-based oleogel (BWO). Differences in L*, a*, and b* values between control oils and the oleogels significantly decreased as the concentration of wax increased in the oleogels (5–15%; p<0.05). Oil-binding capacity of the BWO was higher than that of the CWO. Solid-fat content of the CWO did not change significantly from 10 to 60oC, whereas that of the BWO decreased. In general, oxidative stability of the CWO was better at 60 and 180oC heat treatment in comparison with control oils (p<0.05). However, the BWO did not provide high oxidative stability than the control oils.     

超高压处理对干酪质构的影响

研究超高压(Ultra High Hydrostatic Pressure,HHP;200,600 MPa/10min)处理对5种市售干酪的硬度、黏着性、弹性、内聚性、咀嚼性和回复性6个功能特性的影响。结果显示,5种干酪在200 MPa处理时,其黏着性、弹性、内聚性、回复性差异不显著(P0.05),即较低压力处理对干酪的质构影响不大;超高压处理后,干酪的硬度和耐咀性分别降低31%,39%,且压力越大降低越显著(P0.05);高压处理后蓝纹、稀奶油干酪的内聚性分别增加了21%,15%;帕马森、切达干酪经超高压处理其各个性质基本无显著变化,而马索里拉、蓝纹、稀奶油干酪的各个功能性均有显著差异,说明超高压处理对干酪质构的影响与水分含量有关,即水分含量越高的干酪其质构受超高压处理变化越显著。     

Improving the textural properties of Egyptian kariesh cheese by addition of hydrocolloids

In this study, the effect of addition of hydrocolloids (commercial pectin, citrus pectin or carboxymethylcellulose) to Egyptian Kariesh cheese at 0.2, 0.4 and 0.6% (w/w) on chemical composition, yield, rheological and sensory characteristics was investigated. The results revealed that the addition of hydrocolloids increased moisture content and yield values of Kariesh cheeses compared with control. Protein, salt and ash content decreased with increasing hydrocolloids levels. Rheological characteristics (hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness, resilience) were significantly lower in cheeses made with hydrocolloids. Kariesh cheese made with 0.4% w/w commercial pectin and 0.6% w/w carboxymethylcellulose recorded the highest scores for sensory attributes.     

枝链霉菌S. rameus L2001产木聚糖酶对馒头品质的影响

在馒头制作过程中添加适量枝链霉菌S. rameus L2001产木聚糖酶,研究木聚糖酶L2001对馒头比容、延展率、硬度、含水量、颜色等品质的影响,并进行保存实验。结果表明：木聚糖酶L2001最佳加酶量为0.9mg/kg,此时馒头体积最大且硬度最小,比容比对照增加了9.14%,延展率提高了16.39%,硬度下降了19.0%。在馒头保存实验中,保存时间在10h以内时,硬度、内聚性、胶着性及咀嚼性数值变化缓慢,超过10h,硬度明显增加,内聚性、胶着性及咀嚼性数值有减小趋势。加酶量0.9mg/kg条件下,馒头硬度、内聚性、胶着性及咀嚼性数值均偏小,此时木聚糖酶的抗老化效果最明显。