焙烤工艺对核桃仁品质的影响

以‘温宿185’薄皮核桃为原料,以焙烤后核桃仁的酸值、过氧化值、总酚含量、色泽为指标,并结合模糊数学综合评价法研究焙烤温度、焙烤时间对脱皮与未脱皮核桃仁品质的影响。结果表明:120~140℃、焙烤10~30 min核桃仁的过氧化值和酸值较低;120~150℃条件下随焙烤时间的延长,未脱皮核桃仁与脱皮核桃仁的酸值(KOH)分别在150℃/30 min和150℃/25 min达到最高点,与120℃/10 min相比酸值(KOH)分别上升了0.303、0.107 mg/g;随焙烤温度的升高,核桃仁色泽加深,总酚含量变化不显著,但酚类物质的浸泡液对核桃仁的品质有显著影响;通过模糊数学感官评价法得出核桃仁的最佳焙烤条件为焙烤温度130℃、焙烤时间25 min,在此条件下核桃仁的综合得分为94.10分。焙烤不仅赋予了核桃仁独特的风味,还进一步提升了核桃仁加工制品的品质。     

挤压处理对小麦胚芽多酚及抗氧化性的影响研究

研究挤压过程中挤压条件对小麦胚芽酚类物质及抗氧化性的影响,结果表明:挤压温度对小麦胚芽多酚和抗氧化性产生显著影响(P＜0.05).挤压温度逐渐升高,小麦胚芽总黄酮、总酚和抗氧化能力均呈现下降趋势;物料水分逐渐增大,总黄酮含量和ABTS+自由基清除能力呈先增大后降低的趋势,而对总酚含量、DPPH自由基清除能力和铁还原能力...     

不同炒籽工艺对低芥酸浓香菜籽油风味的影响北大核心CSCD

为了研究不同炒籽工艺对低芥酸浓香菜籽油风味的影响,以低芥酸油菜籽为原料,研究入炒水分、炒籽温度、炒籽时间对低芥酸浓香菜籽油风味物质含量及感官品质的影响。结果表明:从低芥酸浓香菜籽油中共鉴定出65种挥发性风味物质;随炒籽温度上升、炒籽时间延长,低芥酸浓香菜籽油中呈现烤香味的杂环类物质总含量逐渐增加;随炒籽温度上升和入炒水分的增加,呈现刺激味的硫苷降解产物(含硫类化合物、腈类化合物)总含量逐渐增加;在感官上,低芥酸浓香菜籽油主要体现为烤香味、焦糊味,还能感知到腌菜味和刺激味;随炒籽温度升高,低芥酸浓香菜籽油中烤香味感官属性得分先上升后降低,150℃时得分最高,而焦糊味、腌菜味等感官属性得分逐渐升高;随炒籽时间延长,烤香味感官属性得分逐渐降低,焦糊味感官属性得分逐渐升高;随入炒水分增加,烤香味、焦糊味感官属性得分在一定范围内稳定波动。炒籽过程中一定的炒籽温度及增加水分能够明显提升消费者喜好度。     

发酵和焙烤对可可豆多酚、黄酮和风味品质的影响

本实验采用高效液相色谱仪（high performance liquid chromatography,HPLC）、色差仪、电子鼻分别检测未发酵、发酵和焙烤海南可可豆的总酚含量、总黄酮含量、色度和可可豆风味差异。结果表明：未经焙烤的未发酵豆总酚（464.03 mg/10 g）和总黄酮（126.86 mg/10 g）含量明显高于发酵豆总酚（211.86 mg/10 g）和总黄酮（61.98 mg/10 g）含量。105～145 ℃焙烤30 min,未发酵豆总酚和总黄酮含量分别为419.5～129.8 mg/10 g和77.8～16.8 mg/10 g;发酵豆总酚和总黄酮含量分别为182.53～86.25 mg/10 g和34.7～7.0 mg/10 g。其中,125 ℃焙烤20～40 min,未发酵豆总酚和黄酮含量分别为353.74～289.45 mg/10 g和42.86～32.20 mg/10 g;发酵豆总酚和黄酮含量分别为152.08～123.55 mg/10 g和25.12～21.14 mg/10 g。在105～145 ℃的温度焙烤下没食子酸含量变化显著。可可豆色度值的范围：L*值集中在40.0～47.0之间,a*值集中在5.0～6.8之间,b*值集中在4.0～8.5之间。未发酵和发酵可可豆之间,以及不同温度焙烤可可豆之间的电子感官风味分析结果差异较大。     

传统山西老陈醋熏醅工艺过程风味物质及功能活性成分的变化

通过对山西老陈醋熏醅过程中理化指标、风味物质及功能活性成分的测定,分析讨论其变化规律。结果表明,熏醅温度呈现上升趋势,水分含量和pH值呈下降趋势,可溶性固形物、还原糖和氨基酸态氮呈现先上升后下降的趋势,总酸和不挥发酸呈现上升趋势。有机酸总量呈现先下降后上升再下降的趋势,于第4天达到最大值3.35 g/100 g。熏醅的挥发性香气成分共检测出64种,其中31种酯类、6种醇类、5种酸类、10种醛类、3种酚类及9种其他物质。多酚呈现先下降后上升的趋势,熏醅第5天最高为533.06 μg/mL;总黄酮、乙偶姻和川芎嗪的含量呈现上升趋势,第5天达到最大值,分别为627.42 μg/mL、1.06 mg/mL、53.64 μg/mL。     

清酱肉加工过程中理化特性及风味品质的变化分析

以清酱肉为研究对象,从水分活度、剪切力、色泽分析、挥发性风味物质组成和电子鼻分析角度研究清酱肉加工过程中理化特性及风味品质的变化。结果表明:随着加工的进行,清酱肉水分活度整体呈下降趋势;剪切力呈上升趋势且在成熟阶段后升高较为明显;色泽中亮度值和黄度值呈现逐渐降低的趋势,而红度值则先降低后升高;清酱肉挥发性风味物质数量呈现递增的趋势,其中醛类化合物及酯类化合物作为重要的呈味物质呈现逐渐上升的趋势,样品成熟后的酯类化合物含量高达43.59%,醇类化合物相对含量则逐渐减少,酮类化合物及酚类化合物含量变化不大。运用电子鼻技术分析可较好地区分各加工阶段清酱肉的挥发性气味,而利用线性判别分析发现成熟6 d后的样品数据具有一定的相似性。     

热处理对鲜切马铃薯褐变及挥发性物质的影响

褐变是影响鲜切马铃薯贮藏品质的重要因素之一。该研究探讨45、50℃热处理1～4 min对鲜切马铃薯褐变和挥发性风味物质的影响,以期为鲜切马铃薯品质保持提供调控技术和理论依据。45、50℃热处理4 min鲜切马铃薯在室温下2 h就观察到轻微的褐变,L*值下降10.51%、14.96%;a*值上升2.74、3.84,而45、50℃热处理1～3 min组鲜切马铃薯6 h内均未观察到褐变现象。与对照组相比,45℃热处理1～3 min组鲜切马铃薯硬度无显著变化,而其余热处理组硬度显著降低;两种温度1～3 min热处理组鲜切马铃薯苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）酶活性和总酚含量分别降低了27.81%～33.68%、18.33%～50.37%、6.22%～28.92%。45℃热处理1～3min和50℃热处理1～2min热处理组较好的维持鲜切马铃薯原有的挥发性风味物质。总的来说,45、50℃热处理1～3 min可有效的抑制鲜切马铃薯褐变;其中,45℃热处理3 min抑制马铃薯褐变的同时较好维持了硬度、色泽、抗坏血酸含量和挥发性风味物质。     

微波焙烤对藜麦酚类含量及抗氧化性的影响

研究微波焙烤对藜麦"陇藜1号"酚类和抗氧化性的影响。结果表明:微波焙烤对藜麦总酚、总黄酮及抗氧化性有显著影响(P 0. 05);微波功率较低时藜麦总酚含量随着焙烤时间延长而增加,功率较高时则相反;总黄酮含量随着微波焙烤功率升高和时间的延长而降低;微波功率较低时藜麦抗氧化性随着焙烤时间延长而增强,功率较高时则相反;总酚含量与藜麦抗氧化性呈极显著正相关(P 0. 01),总黄酮含量与藜麦抗氧化性相关性不显著(P 0. 05)。     

焙烤条件对超临界CO_2萃取油茶籽油品质的影响

以普通油茶籽和浙江红花油茶籽为试材,探讨了焙烤条件对超临界CO2萃取油茶籽油品质的影响。研究结果表明:当焙烤温度为150～210℃,焙烤时间为5～20 min时,超临界CO2萃取(45℃,25 MPa)油茶籽油随温度和时间的增加其色泽逐渐加深,从嫩黄色转变为铜红色,气味从青草味转变为烤花生味和芝麻糊味;随着焙烤温度和时间的增加,油茶籽油过氧化值呈降低趋势,酸值则随不同品种的油茶籽而不同,但二者的值均较低;焙烤时间对油茶籽油水分及挥发物含量的影响比较明显。综合各指标,较适合的焙烤条件为170℃焙烤10～15 min。     

恒温及变温复水方式对脱水薇菜品质及复水动力学的影响

为探究复水方式对薇菜品质及复水动力学的影响,论文研究了恒温复水与变温复水条件下薇菜复水率、质构特性以及营养物质含量变化,并利用Weibull模型对复水过程进行拟合。结果表明:在恒温复水方式下,随温度升高,薇菜的水分含量升高,硬度、弹性、咀嚼性、还原糖、可溶性蛋白、总酚含量均降低,而抗氧化性先升高而后降低;在变温复水方式下,随温度升高,薇菜的水分含量与抗氧化性增大,硬度、弹性、咀嚼性、还原糖、可溶性蛋白、总酚含量均略有降低;变温复水方式下薇菜的品质高于恒温复水。Weibull模型能较好地模拟不同复水方式下薇菜复水过程。     

酸处理对烤马铃薯条品质的影响

为了改善烤马铃薯条品质，选用不同质量分数的柠檬酸、苹果酸、醋酸溶液预处理马铃薯条，通过测定烤后马铃薯条的质构、水分分布等品质指标以探究酸处理对烤马铃薯条的作用规律。结果表明，酸浸泡处理减缓了烤制对马铃薯细胞的破坏，烤马铃薯条的孔隙减少，硬度升高。质量分数越高，烤马铃薯条失重率越大（P<0.05），水分流失越严重，2%醋酸处理5 h失重率高达（57.83±1.49）%；随浸泡时间的延长，烤马铃薯条硬度和剪切力均增加（P<0.05），浸泡5 h时微观结构最为致密；柠檬酸和苹果酸浸泡有助于烤马铃薯条产生花香味和蘑菇味。     

马铃薯粉对面包烘焙特性与风味化合物的影响

以小麦面包为对照,研究马铃薯粉添加量为15%对面包烘焙特性的影响,并应用电子鼻以及顶空固相微萃取-气相色谱-质谱联用技术,分析马铃薯面包挥发性风味化合物的特征。结果表明,马铃薯粉的添加对面包的品质影响显著,马铃薯粉使面包的比容提高到4.12 mL/g,水分含量增加了7%,硬度减小了6 N,水分活度降低,面包的色泽和总体可接受程度明显提高,保质期和烘焙品质得到有效改善;对于风味,电子鼻主成分贡献率为97.3%,说明电子鼻能够很好地区分小麦面包和马铃薯面包的风味;顶空固相微萃取-气相色谱-质谱分析结果表明小麦面包和马铃薯面包的主要挥发性成分为酯类物质,添加马铃薯粉使各类风味化合物的相对含量发生变化,其中马铃薯面包中含有异薄荷酮、对薄荷-3-烯、1-甲基-4-(1-甲基亚乙基)-环己烯、丙二酸二乙酯等风味化合物,烯烃类物质相对含量和种类明显增多。     

IDENTIFICATION OF IMPORTANT PRODUCTION VARIABLES AFFECTING HARD PRETZEL QUALITY

The objective of this study was to determine the importance of raw material and processing variables that influence pretzel quality by utilizing a screening experiment design. Eleven variables were selected based on preliminary experiments, and a two‐level‐11‐factor (2 ¹¹ ) fractional factorial experimental design was used to screen the variables. Several responses were measured for dough before and after extrusion, for half‐baked and fully baked pretzels. These responses are important indicators of consistency and quality during pretzel processing. Results indicated that flour protein content, the amount of water added to make dough and dough mixing time were important variables influencing dough behavior. Caustic concentration affected brightness of half‐baked pretzels but did not influence the color of the final product. Baking time was the most important factor for both half‐baked product and final product qualities. The hardness of fully baked pretzels was influenced by baking time, temperature in baking oven zone 1, drying time and drying temperature. The color of final products was significantly influenced by baking time, while both baking time and drying temperature affected the moisture content of the final product. A key observation was that none of the raw material or dough processing parameters, within the range tested, influenced final pretzel quality as defined by pretzel moisture content, hardness or color.     

EVALUATION OF THE TEXTURE OF FRIED POTATOES

Texture of potatoes with different shapes (slices and strips) were evaluated after frying and in some cases after baking. Blanched and unblanched potato slices (Bintje variety) were fried at four oil temperatures: 160, 170, 180 and 190C until reaching a moisture content of ∼1.7%. A puncture test with three point support for the slices was applied to measure the texture of potato chips using the following parameters extracted from the force versus distance curves: maximum force of break (MFB) and deformation of break (DB). These two parameters were useful to follow the changes in texture of the fried slices with moisture content at different frying temperatures. Blanched and unblanched potato strips were partially fried at 160C and 190C for 60, 90 and 120 s. The par-fried potatoes were frozen at -20C for one day after which they were baked at 200C for 15 min. The texture of the baked potato strips was evaluated using a bending test with two support points. From the force versus distance curves, two parameters were extracted: maximum force of deformation (MFD) and maximum deformation (MD). Significant higher MFB and lower DB values (P > 0.1) for unblanched fried slices indicate that these are crispier than blanched chips for moisture contents lower than 4% (6.59 N and 0.62 mm vs 5.74 N and vs 0.75 mm for unblanched and blanched chips, respectively, average values for the four frying temperatures employed). There was no effect of the frying temperature and the pretreatment (blanching or unblanching) on the texture of the frozen par-fried potatoes after baking when compared at the same residual moisture content, but blanched potato strips lost moisture more slowly both in frying and in baking.     

Effect of Radio Frequency Postdrying of Partially Baked Cookies on Acrylamide Content,Texture, and Color of the Final Product

Abstract: Effect of radio frequency (RF) postdrying of partially baked cookies on acrylamide content, texture, and color of the final product was investigated in this study. Control cookies were prepared by baking in a conventional oven at 205 °C for 11 min. Cookies partially baked for 8 and 9 min were postdried in a 27.12 MHz RF tunnel oven until attainment of the moisture content of control cookies. Internal temperature of cookies was monitored during the experiments to better explain the results. Cookies were analyzed for acrylamide content using a liquid chromatography‐mass spectrometry (LC‐MS) method. Texture measurements were performed using a Texture Analyzer, while digital image analysis was used for color measurement. The results showed that RF postdrying of partially baked cookies resulted in lower acrylamide levels (107.3 ng/g for control cookies, 74.6 ng/g upon RF postdrying of cookies partially baked for 9 min, 51.1 ng/g upon RF postdrying of cookies partially baked for 8 min). Instrumental texture analysis showed no significant difference among the texture of cookies, whereas RF postdried samples had a lower degree of browning. According to sensory evaluation results, control had a more crumbly texture, and RF postdried sample that was conventionally baked for 8 min had a slightly uncooked flavor. Practical Application: Combining radio frequency and conventional baking may provide cookie manufacturers with ability to make cookies with lower levels of acrylamide.     

Halogen lamp–microwave combination baking of cookies

The effects of halogen lamp–microwave combination baking on the quality of cookies in terms of texture, color and spread ratio were studied. In addition, gelatinization and pasting properties of cookies baked in different ovens were assessed by using a Rapid Visco Analyzer. The hardness values of the cookies increased with increasing baking time and/or halogen power. The microwave power also contributed to cookie hardness. The lightness values of the cookies decreased, while the a* and E values increased linearly during baking at different halogen lamp and microwave powers. The spread ratio of conventionally baked cookies was significantly lower than that of the other cookies. Halogen lamp power, microwave power and baking time were found to have a significant effect on the spread ratio of the cookies. The moisture contents of the cookies decreased during baking as the halogen lamp and/or the microwave power level increased. The best baking condition in a halogen lamp–microwave combination oven to produce cookies having similar quality parameters as conventionally baked ones was baking at 70% halogen lamp and 20% microwave power levels for 5.5 min. The baking time of these cookies is half of that required in conventional baking.     

TIMED COLOR CHANGES AMONG RAW AND BAKED POTATO VARIETIES

Color changes in twenty two lines of potatoes by the browning reaction were measured and evaluated by Hunter color value and National Bureau of Standard (NBS) unit of color difference (ΔE). The relationship between color change and total solids content was evaluated (p < 0.05). CO87106–5 and AC87313–3 contained the highest solids content, while CO86218–2 and CO82142–4 had the lowest solids content. Overall color change in raw potatoes by browning showed CO86142–3 with the least color change and AC87084–2 with the most. Hunter color values for the browning reaction changed with time. As time increased, potatoes became darker, redder and bluer. Moreover, all of the Hunter color values were significantly changed by baking. Color of baked BC0894–2, CO86142–3 and CO87106–5 were the least changed, while that of the baked CO8001–5, Russet Norkotah and TC1406–1 were the most changed. Degree of browning in raw potato was not correlated with total solids content, but did show a negative relationship (r =−0.12). Also, rate of color change by the browning reaction in raw potato was not related to potato total solids (r =−0.10). Color change by baking also was not correlated with total solids content (r =−0.36). Raw potato color change was positively correlated to baked potato color change (r = 0.42). Genotype of the potatoes was closely related with     

挤压变量对马铃薯方便粥品质特性的影响

以马铃薯全粉、大米粉为主要原料,采用双螺杆挤压微膨化工艺,联用常压连续气流膨化技术开发马铃薯方便粥.研究了马铃薯全粉含量、挤压温度、水分含量对马铃薯方便粥品质特性的影响,并采用因子分析法对马铃薯方便粥的品质特性指标进行综合评价.结果表明:随着马铃薯全粉含量、挤压温度的升高,马铃薯方便粥的颜色均逐渐加深,质构特性逐渐降低...     

马铃薯蒸馍的配方优化

为了开发高含量马铃薯泥主食制品,本文探究了马铃薯泥含量为50%的马铃薯蒸馍的最优配方。以面团发酵特性、蒸馍感官评分、质构和色差等为指标,采用单因素和正交试验优化了马铃薯蒸馍配方。结果表明,随着谷朊粉含量增加,面团比容先增大后减小、宽高比先减小后增大,蒸馍的硬度、胶着度和咀嚼度先减小后增大,感官评分先增大后减小;随着棕榈油和酵母含量增加,面团比容增大、宽高比减小,蒸馍的硬度、胶着度和咀嚼度和感官评分增大。正交试验优化得到蒸馍的最佳配方为:马铃薯薯泥50%、面粉30%、谷朊粉5%、水7%、棕榈油4%、酵母3.5%、小苏打0.2%、盐0.3%,在此条件下得到的马铃薯蒸馍的感官评分为90.50分,蒸馍表面光滑、色泽亮丽均匀、外观挺立饱满并且具有马铃薯香气。本研究结果可为马铃薯主食化加工提供了理论基础。     

Acrylamide formation and colour development in low-fat baked potato products as influenced by baking conditions and oil type

The objective of this study was to investigate the effect of oil type and oxidation status on acrylamide (AA) formation and colour development in potato products under domestic baking conditions. Sunflower, soybean and olive oil were used; the first one was thermally oxidized to obtain different oxidation status. A potato dough containing 10 % oil, potato powder, flour and water was shaped into thin discs and baked at 180 °C for different heating times. AA concentration, moisture content and surface colour were determined. Results obtained showed that neither the nature of lipids present, in terms of content of unsaturated fatty acids, nor the degree of fat oxidation influenced AA formation in low-fat baked potato products. Browning ratio higher than 45 % and moisture content lower than 17 % resulted in dark brown, almost burnt, products. Moreover, in those cases, no correlation could be found between those variables and AA content, since formation and degradation simultaneously occur. When the browning ratio ranged between 0 and 45 %, a good linear correlation with AA formation was observed, suggesting that the browning ratio may be considered as a reliable indicator of AA concentration. Finally, AA less than 1000 μg/kg, which is an indicative value that has been recently set for potato crisps by the European Commission, corresponds to a browning ratio of less than 8 % and moisture content more than 23.5 %.