牛排熟制条件的数字化模型的建立

本实验旨在探讨煎制温度、煎制时间对牛排中心温度的影响。通过对一定大小的牛排在不同煎制条件下的中心温度进行测定,并对测定结果进行分析,本实验初步建立了牛排熟制条件的数字化模型。结果表明,煎制温度各水平间、煎制时间各水平间差异均达到1%的显著水平,但两因素的交互效应不显著。     

调理牛排煎制过程中的保水性及水相分布特征

利用低场核磁共振(Low-field nuclear magnetic resonance,LF-NMR)技术检测调理牛排煎制过程中水的横向驰豫时间T₂,区分调理牛排中水分分布状态,同时以加压失水率和烹调损失率为指标来测定调理牛排煎制过程中的保水性变化。结果表明:6组不同熟度调理牛排之间的加压失水率和烹调损失率均存在显著性差异(p<0.05);随着煎制温度的升高及时间的延长,牛排的加压失水率和烹调损失率不断增高,3种水分状态对应的T₂弛豫时间均向慢弛豫方向移动,水的自由度和流动性不断的增高,而结合度在不断的降低,即牛排体系对水分的束缚能力降低;且调理牛排的成熟度越大,T₂₂状态的水分弛豫时间移动越明显。     

真空低温慢煮牛排的工艺优化研究

以牛肉为原料,通过单因素和正交试验研究了低温慢煮牛排加工工艺的优化。结果表明,最佳工艺条件为:腌制时间25 min,慢煮温度50℃,慢煮时间55 min,煎制时间60 s。此外,以感官评价、烹饪损失率、熟肉率、剪切力、TPA物性及挥发性气味为指标,研究了直接煎制、拍打后煎制和低温慢煮牛排对牛排品质的影响。结果表明,低温慢煮牛排的感官评价和嫩度最佳,烹饪损失率最低,此时牛排的风味能最大限度地体现出来。真空低温慢煮方法可以更好地保留牛肉的风味,有利于其在牛肉产品方面的广泛应用。     

不同加工方式对煎制重组牛排食用品质的影响

为研究不同加工方式对西餐红肉煎制重组牛排食用品质的影响,采集中国西门塔尔公牛和甘南牦牛的后腿部位肉,研究粘合肉块直径大小、切片厚度及熟制终点温度对煎制牛排剪切力(warner-bratzler shear force,WBSF)、质构剖面分析(texture profile analysis,TPA)的影响。结果表明:粘合肉块直径的大小显著影响牛排的食用品质特性(p0.05);牛排剪切力随切片厚度增加而增加(p0.05);牛排的剪切力、蒸煮损失和硬度随熟制温度的升高而增加(p0.05)。根据熟肉率、剪切力、硬度的结果,选择煎制重组牛排的较佳粘合肉块大小直径为5 cm左右、切片厚度为8 mm和熟制温度为60℃。按此工艺生产的重组牛排具有较好的质构特性,熟肉率高,嫩度好。     

不同熟度重组及调理牛排食用品质差异分析

为研究不同熟度重组及调理牛排间的品质差异,将两种牛排分别煎制到不同熟度,分析其在不同熟度下的烹饪损失、色泽、质构特性以及蛋白质的消化性,并建立感官评价小组进行感官评价。结果显示,牛排烹饪损失率随熟度显著升高,七成熟的调理牛排显著高于重组牛排。硬度、咀嚼性、胶着性随熟度增幅较大,内聚性、弹性、回复性差异不大。牛排中蛋白质的胃、肠、总消化率都随熟度呈先升高后降低的趋势,在五成熟达到最大值,胃消化率在五成熟后下降差异不显著,肠消化率和总消化率在五成熟后显著下降。同时调理牛排消化率显著高于重组牛排。牛排的L*值和b*值都随熟度增大先升高后趋于平稳,a*值先升高后逐渐降低。感官综合得分先增大后降低,七成熟的牛排得分最高。综上所述,牛排的食用品质随熟度增大呈先变好,在五成熟后逐渐降低。当牛排煎制五成熟时,建议消费者选择调理牛排。当牛排煎制七至十成熟时,建议消费者选择重组牛排。     

煎香肠中杂环胺的生成规律研究

目的 考察不同煎制温度、时间和不同食用油对煎香肠中杂环胺(heterocyclic amines, HAs)生成的影响, 并进一步探究几种常见香辛料对煎香肠中HAs生成的抑制效果。方法 采用超高效液相色谱-串联四极杆质谱法(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)对煎香肠中游离和结合态HAs进行定量分析, 评价各因素对煎香肠HAs生成的影响。结果 煎香肠中游离态HAs总量随煎制温度或时间的增加而逐渐增加, 结合态HAs总量随煎制温度升高而增加, 随煎制时间延长先减少后增加。相比于不采用食用油煎制, 添加大豆油对煎香肠游离态HAs抑制效果最好, 抑制率达37.25%; 同时对结合态HAs促进作用最小, 仅促进7.13%。辣椒粉和大蒜能显著促进煎香肠游离态和结合态HAs生成(P<0.05), 而添加0.5%黑胡椒粉时对游离态和结合态HAs的抑制率分别为25.49%和25.32%。结论 相比于时间, 温度对煎香肠HAs影响更为显著(P<0.05); 采用大豆油煎制的同时添加黑胡椒可明显抑制煎香肠中游离和结合态HAs的生成。     

煎制成熟度对牛排挥发性风味物质及感官的影响

采用感官评价以及固相微萃取-气相色谱-质谱联用技术,通过热图结合相对气味活度值对不同煎制成熟度牛排(一分熟、三分熟、五分熟、七分熟和九分熟)中挥发性风味物质和感官品质进行分析。结果表明,煎制时间的延长促进了牛排色泽、滋味和香气的生成,但牛排的嫩度逐渐变小;七分熟牛排的感官评分最高,挥发性风味物质含量与数量也最高。煎制牛排中关键挥发性风味物质为1-辛烯-3-醇、辛醛、壬醛、(E)-2-壬烯醛、(E)-2-癸烯醛、(E,E)-2,4-壬二烯醛、2-十一烯醛、(E,E)-2,4-癸二烯醛、3-庚酮、己酸等,醛类物质种类最多,可能是煎制牛排风味形成的重要组成部分;随煎制程度增加,牛排的蘑菇香、花香、奶油香减弱,总体香味以油脂香和肉香为主。由感官评价和相对气味活度值聚类分析可知,三分熟和五分熟为一类,七分熟和九分熟为一类,一分熟样品与其他样品存在较大差异。不同煎制牛排样品中蛋白质、脂肪和碳水化合物含量存在显著差异,且与挥发性物质的形成密切相关。     

响应面分析法优化海鳗的湿腌工艺

目的:优化鳗鱼肉湿腌工艺条件,为鳗鲞生产提供理论依据。方法:以腌制后鱼肉盐溶性蛋白含量、氯化钠含量、盐卤中蛋白质含量为指标,通过单因素试验及响应面分析法,研究不同腌制条件(时间、温度、盐度)对鳗鱼肉品质的影响,并建立感官评定结果与测定指标间的数学模型,以优化湿腌工艺条件。结果表明:1)鱼肉氯化钠含量及盐卤中蛋白质含量与腌制时间、温度和盐水浓度呈正相关;腌制时间、温度对鱼肉盐溶性蛋白含量有一定影响。2)采用响应面分析法建立感官评定与腌制条件的数学模型,曲面回归方程拟合性好。对感官评定结果的影响:盐水浓度极显著,腌制时间较显著,而腌制温度不显著。3)通过响应面交互作用分析与优化,最佳腌制条件:腌制时间0.91h、温度9℃、盐度13.50%,所得鳗鲞的感官评分值与模型预测值基本相符。结论:腌制时盐水浓度对鳗鲞感官评定结果的影响极显著,鳗鱼肉湿腌的最适盐度为13.50%。     

切割角度和制熟方式对牛排品质因子及挥发性风味物质的影响

选用科尔沁西冷牛肉,将其按照与肌纤维平行、垂直以及45°3种角度切割,并分别采用烤制、煎制、微波加热的方式制熟,对不同切割角度及制熟方式下牛排的品质因子(色泽、质构、烹调失水率)和挥发性风味物质进行测定与分析。结果表明,在色泽方面,制熟方式对牛排的色差有显著影响,烤制成熟且垂直肌纤维切割的牛排烹饪失水率最低,牛排持水力较好;在物理性质上,垂直肌纤维切割的牛排经过烤制后其剪切力、硬度和咀嚼性均最小,分别为14.48 N,110.00N,283.27mJ;在风味物质方面,不同切割方式及加热方式中牛肉挥发性物质种类和含量有较大区别,以垂直肌纤维切割、烤制的牛排中醛类、醇类、酯类含量最高,分别为70.19%,8.20%,6.86%,并且其种类也最多;同时,微观表征也证明了垂直肌纤维切割、烤制的牛肉肌纤维紧密度较高,肌束膜间隙较小,食用品质最佳。     

超临界CO_2法萃取芹菜叶黄酮

在考察超临界CO2萃取温度、萃取压力、萃取时间以及夹带剂用量等单因素对黄酮萃取率影响的基础上,采用Box-Behnken响应曲面设计法,建立影响因素和黄酮得率之间的回归方程。结果表明:萃取温度、萃取压力、萃取时间对超临界CO2萃取芹菜中黄酮工艺影响极显著,夹带剂用量影响显著,最佳提取工艺条件为萃取温度70℃、萃取压力30 MPa、萃取时间2.5 h、夹带剂用量为1 mL/g。该条件下黄酮得率为9.03%,与预测值相近,差异不显著,符合实验要求。     

Optimization of processing conditions for vacuum frying of high quality fried plantain chips using response surface methodology (RSM)

Optimization of processing conditions (temperature 122 to 136°C, vacuum pressure 9.91 to 19.91 cmHg, and frying time 3 to 9 min) during vacuum frying of plantain chips was investigated using a Box-Behnken experimental design with response surface methodology (RSM). Models for various responses were developed and optimized frying conditions using numerical solutions were established. Optimized vacuum fried samples were compared with atmospheric fried samples based on the concept of equivalent thermal driving force (ETDF). Frying parameters had significant (p<0.05) effects on the moisture content, texture, and color with a coefficient of determination (R ²) for quadratic model responses varying between 0.53 and 0.99. Optimum vacuum frying conditions for plantain chips were a frying temperature of 133°C, vacuum pressure of 9.91 cmHg, and frying time of 6 min based on desirability concepts. Vacuum fried plantain chips had more acceptable sensory properties, based on ETDF values, than atmospheric fried samples.     

DEEP-FAT FRYING OF YAM SLICES: OPTIMIZATION OF PROCESSING CONDITIONS USING RESPONSE SURFACE METHODOLOGY

The deep-fat frying of yam slices was investigated with the aim of optimizing the processing conditions. During frying, frying temperature, initial dry matter and frying time have a significant effect on moisture loss and oil uptake. Response surface methodology central composite rotatable design was used to study the effects of the independent variables on quality attributes of yam chips. Breaking force, oil content, moisture content and color parameters were determined. Statistical analysis with response surface regression showed that breaking force, oil and moisture contents and color parameters ( L* and a* ) were significantly ( P <  0.05) correlated with frying temperature, initial dry matter and frying time. The optimum conditions were a frying temperature of 175–180C, using tubers of initial dry matter of 0.179–0.214 kg/kg with a frying time of 4–5 min. It was suggested that the regression equation can be used to estimate the dependent variables for fried yam chips except b* (yellowness) parameter.

PRACTICAL APPLICATIONS

It is expected that the optimized processing conditions highlighted in this work will be useful in obtaining fried yam chips of acceptable quality attributes. This optimized condition would be a good prospect for commercialization in small-scale industries.     

番茄浆料的流变特性

对不同浓度的番茄浆料在30～60℃时的流变学性质进行了研究.结果显示,番茄浆料为假塑体系,屈服应力值的范围比较宽(40～140Pa).通过回归分析得到数学模型K=K0exp(Ea/RT)和K=Aexp(BC).可以分别用来描述温度和浓度对番茄浆料稠度系数的影响.利用这些方程,可以预测实际加工过程中不同温度和不同浓度条件下番茄浆料的粘度.     

Optimisation of vacuum frying of gold kiwifruit slices: application of response surface methodology

Response surface methodology was used to investigate the effects of the level of maltodextrin (MD), frying temperature and time on the moisture, colour and texture properties of the vacuum‐fried gold kiwifruit slices and to determine the optimised conditions for vacuum frying. The moisture content of vacuum‐fried gold kiwifruit slices decreased with increasing frying temperature and frying time. The colour change of the product increased with increasing frying temperature. The browning index of the product increased with increasing frying temperature and frying time. The breaking force of the product gave higher values when processed at middle range of frying temperature and MD level. When processing vacuum‐fried gold kiwifruit slices, there was a need to use frying temperatures of 72.0–76.3 °C, frying times of 35.0–65.0 min and an MD level of 40% to achieve products with acceptable moisture, colour and texture properties.     

不同加热方法对大米主要化学成分及食味的影响

以大米为对象,研究常规加热、微波加热和混合加热对不同品种大米品质的影响,为微波防虫防霉和生产应用提供参考。结果表明,加热方法和品种对大米品质的影响有差异,水浴加热对大米品质的影响大于微波处理。在试验范围内,先用常规加热将大米预热,再用微波处理的混合加热法对大米品质的影响小于单独加热。预热后大米温度、微波功率和微波加热时间对大米品质有极显著或显著影响。建立了预热后大米温度、微波功率和微波加热时间与大米的水分含量、直链淀粉含量等主要化学成分和食味之间的多元线性回归方程,具有较高的拟和精度。     

STORAGE OF RETORT POUCH BEEFSTEAK AND BEEF STEW PACKED UNDER FOUR HEADSPACE LEVELS

Changes in specific physico-chemical and sensory attributes as well as acceptability of beefsteak and beef stew Meal-Ready-to-Eat (MRE) components packed under different headspace levels (10, 20, 30 and 40 cm³) and stored at selected temperatures of 4, 27 and 38C (40, 80 and 100F) were evaluated over a six month period. No significant changes in microbial counts, pH, residual oxygen, color, hardness and oxidation occurred in retort-packed beefsteak or beef stew. Unlike beefsteak, beef stew received acceptable scores by consumers during all six months of analysis. Consumers' lack of familiarity with beefsteak may have negatively influenced product acceptability. Beefsteak and beef stew acceptability and specific attributes, particularly moistness and firmness, were detrimentally affected by high storage temperatures. Headspace may be increased to 40 cm³ without significant detrimental effects on product quality and acceptability of beefsteak or beef stew.     

油炸温度和时间对猪肉块品质的影响

本文研究了不同油炸温度和时间对猪肉块品质的影响,分析了150、165和180℃条件下油炸不同时间后猪肉块的色泽、硬度、水分含量、脂肪含量、蛋白质羰基含量、硫代巴比妥酸值(TBARS值)和挥发性醛类物质的变化情况。实验结果表明,油炸后猪肉块的亮度降低,红度和黄度升高;硬度在油炸过程中变化显著(p<0.05),150℃油炸470 s时达到最大值37.59 kg;150、165和180℃分别油炸470、330和230 s后猪肉块的水分含量减少了56.25%、52.82%和48.92%(p<0.05),高温短时油炸条件下水分损失较少;脂肪含量在150、165℃时随时间变化不显著,180℃油炸时随时间的延长显著增加(p<0.05);蛋白质羰基含量随油炸时间的延长而增大,180℃油炸150 s时猪肉块的蛋白质羰基含量为2.17 nmol/mg;TBARS值和己醛含量在油炸后迅速增大,之后呈现先减小后均大的趋势,180℃油炸150 s的TBARS值为0.71 mg MDA/kg;挥发性醛类物质中己醛与TBARS值相关性显著,150、180℃条件下的相关系数分别为0.962和0.997。180℃油炸150 s时的猪肉块具有金黄的色泽,硬度适中,脂肪和蛋白质氧化程度较小,具有较好的品质。     

The optimization of vacuum frying to dehydrate carrot chips

The effects of pretreatment and processing conditions, such as frying temperature, absolute vacuum pressure and frying time; on the properties of fried carrot chips were studied. Statistical analysis with response surface regression showed that moisture content, fat content and breaking force of carrot chips were significantly (P < 0.05) correlated with frying temperature, vacuum absolute pressure and frying time. The optimum conditions were a vacuum frying temperature of 100–110 °C, a vacuum absolute pressure of 0.010–0.020 MPa and a frying time of 15 min.     

Effects of processing conditions on the quality of vacuum fried apple chips

The effects of pretreatment and processing conditions on the quality of vacuum fried apple chips were studied. As blanched apple slices were pretreated by immersing in fructose solution and freezing prior to vacuum frying, more uniform porosity was observed on the surface (or cross-section) of apple chips as examined by scanning electron microscopy (SEM). During vacuum frying, the moisture content and breaking force of apple chips decreased with increasing frying temperature and time while the oil content increased. The L values of fried apple chips decreased apparently with increasing frying temperature. However, when apple slices were fried at 100°C for up to 20 min, both a and b values increased rapidly. Statistical analysis with the central composite rotatable design showed that the moisture content, oil content, color, and breaking force of apple chips were significantly (P⩽0.05) correlated with concentration of immersing sugar solution, frying temperature and frying time. Based on surface responses and contour plots, optimum conditions were: vacuum frying temperature of 100–110°C, vacuum frying time of 20–25 min, and immersing fructose concentration of 30–40%.