Pigment Changes in Fried Dough Containing Spinach Powder During Storage in the Dark

ABSTRACT: Changes in chlorophyll and carotenoid contents of fried dough supplemented with spinach ( Spinacia oleracea ) powder were investigated during storage. Flour dough containing spinach powder was fried in soybean oil at 160 °C for 1 min and stored in a glass bottle at 60 °C incubator in the dark up to 12 d. Chlorophyll contents decreased with storage time, whereas pheophytin contents increased followed by decrease. Decomposition of chlorophyll a was faster than that of chlorophyll b. Carotenoids were decomposed during storage; however, the decomposition rate was lower than that of chlorophylls. Decrease in carotene contents with storage time was slower than that in xanthophylls.     

Lipid Oxidation and Carotenoids Content in Frying Oil and Fried Dough Containing Carrot Powder

ABSTRACT: Lipid oxidation and carotenoids in frying oil and carrot-added dough during frying were studied. Flour dough containing carrot powder was sheeted at 0.1 cm thickness and was then cut to squares to be fried. Each frying was performed in 160°C soybean oil for 1 min and repeated every 20 min for 20 h. Carrot in the dough decreased significantly the oxidative stability of frying oil and fried dough (p < 0.05). Carotenoid content in frying oil increased as frying was repeated due to dissolution of carotenoids from the dough containing carrot; however, there was no significant difference in carotenoid content among the dough fried in the oil with different number of fryings.     

Oxidative stability of fried dough from rice flour containing rice bran powder during storage

The aim of this study was to evaluate the efficiency of rice bran powder on lipid peroxidation inhibition of fried dough from rice flour during storage. Rice flour dough containing rice bran powder at 5, 10 and 15 g rice bran powder/100 g mixed rice flour were fried in soybean oil at 160 °C for 1 min and stored in dark at 60 °C for 10 days. Lipid peroxidation of fried dough was determined by change of fatty acid compositions, oxygen absorption in vial headspace, lipid hydroperoxides, TBA values including decreasing tocopherol and gamma-oryzanol contents during storage. Polyunsaturated fatty acid decreased rapidly in fried dough without rice bran powder, while an increase of oxygen absorption in vial headspace, lipid hydroperoxide and TBA values were significantly lower (p?0.05) in fried dough containing rice bran powder. In addition, tocopherol degradation was significantly lower in fried dough containing rice bran powder during storage (p?0.05). However, there was no significant difference in gamma-oryzanol contents among fried dough during storage (p>0.05). These results demonstrated that rice bran powder shows the antioxidative effects on fried dough during storage.     

Effects of the Number of Fryings on Pigment Stability in Frying Oil and Fried Dough Containing Spinach Powder

ABSTRACT Chlorophylls and carotenoids in dough containing added spinach powder and fried, were determined by high performance liquid chromatography and spectrophotometry, respectively. Sixty-one batches of flour dough were fried for 1 min every 20 min in 160 °C soybean oil. Chlorophyll was not detected in the oil during frying. Carotene contents, however, increased with the number of fryings. Chlorophyll contents in the dough fried in soybean oil decreased with more fryings, while there was little difference in carotenoid contents. The results showed that only carotenoids diffused out of the dough in the previous frying could contribute to the pigment contents in the fried dough of the next batch.     

Effects of Sesame Oil Addition to Soybean Oil During Frying on the Lipid Oxidative Stability and Antioxidants Contents of the Fried Products During Storage in the Dark

ABSTRACT: Effects of sesame oil addition to soybean oil during frying on the lipid oxidative stability and antioxidants contents of fried products during storage in the dark were studied. Flour dough pieces (2 cm × 2 cm × 0.1 cm) were fried at 160 °C for 1 min in sesame oil-added soybean oil. Concentrations of sesame oil in the frying oil were 0%, 10%, and 20% by volume. Fried products were put into a glass bottle, and the bottles were tightly sealed and stored at 60 °C in the dark for 18 d. Lipid oxidation of fried products was determined by fatty acid composition changes and conjugated dienoic acid (CDA) and p -anisidine (PA) values. Tocopherols and lignan compounds in the fried products were determined by high-performance liquid chromatography. Relative content of linolenic acid decreased, and CDA and PA values increased during storage of the fried products in the dark. Fatty acid composition change and CDA and PA values during storage were lower in the products fried in sesame oil-added soybean oil than in the products fried in soybean oil without sesame oil. The results clearly showed that addition of roasted sesame oil to soybean oil at 10% and 20% during frying decreased the lipid oxidation of fried products during storage in the dark for 18 d by extension of induction period and decrease in decomposition of oxidized lipids. Fried products contained 134 to 267 ppm tocopherols and 0 to 148 ppm lignans before storage; however, their contents decreased during storage in the dark. Lignan compounds were more stable than tocopherols, and the rate of tocopherols degradation was lower in the products fried in sesame oil-added soybean oil than in the products fried in soybean oil without sesame oil, which could be because of protection of tocopherols from degradation by lignan compounds.     

Oxidation of corn oil during frying of soy-flour-added flour dough

ABSTRACT:  Oxidation of corn oil during frying of soy–flour-added dough was studied. Flour dough containing soy flour at 0%, 10%, 20%, and 30% was fried in corn oil at 180 °C for 2.5 min, and a total of 60 fryings were performed every 30 min. The oxidation of oil was determined by contents of free fatty acids (FFA), conjugated dienoic acids (CDA), polar compounds, and p -anisidine values (PAV). Tocopherols and phospholipids (PLs) in the oil were determined by HPLC. Tocopherols were present in corn oil at 1000 ppm before frying and increased after the first frying of dough containing soy flour due to tocopherol transfer from soy–flour-added dough to the oil during frying. However, as the oil repeated frying, tocopherol contents decreased and its degradation rate was higher in the oil that fried soy–flour-added dough than in the oil that fried the dough without soy flour. PL was not detected in corn oil before and after frying. As the oil repeated frying, FFA, CDA, and polar compounds contents, and PAV of frying oil increased due to the oil oxidation. The values were higher in the oil which fried soy–flour-added dough than in the oil fried the dough without soy flour, indicating the acceleration of oil oxidation by soy flour added to dough. Increase in the oil oxidation by soy flour added to the dough was highly correlated with fast decomposition of tocopherol in the oil.     

基于模糊数学感官和响应面法研制豆渣麻花及品质分析

本文以豆渣粉和中筋粉为主要原料,辅以泡打粉、植物油、蔗糖、全蛋液进行豆渣麻花的研制.在单因素实验的基础上,利用模糊数学感官评价法和响应面优化法对影响豆渣麻花感官品质的蔗糖添加量、植物油添加量、豆渣粉添加量进行优化,并对最后成品的营养成分、理化指标和微生物指标进行相关测定.豆渣麻花的最佳工艺配方为:豆渣粉添加量14％(豆...     

Dynamic Rheological and Thermal Properties of Soft Wheat Flour Dough Containing Structured Lipid

ABSTRACT: The effect of substituting canola oil/caprylic acid structured lipid for shortening (at 0%, 25%, 50%, 75%, and 100% levels) on the viscoelastic and thermal properties of soft wheat flour dough (28.4% total lipid, 43% moisture) was determined using dynamic rheological and differential scanning calorimetry tests. Ambient frequency scans produced higher G" (loss modulus) and G' (storage modulus) values at increasing frequencies. Temperature scans revealed rapid G" and G' increases for dough heated to above 56 °C, apparently because of starch gelatinization. Three differential scanning calorimetry endothermic peaks were observed at 54 °C, 69 °C, and 93 °C, which were attributed to shortening transition and gelatinization of starch granules.     

Effects of egg yolk powder addition to the flour dough on the lipid oxidation development during frying

Effects of egg yolk powder added to the dough on the oxidation of frying oil and lipid of fried products were studied. Flour dough containing egg yolk at 0, 3.53, 6.73, and 9.66/100 g was fried in 180 °C sunflower oil for 1.5 min, and 55 fryings were performed. Lipid damage was determined by free fatty acids (FFA), conjugated dienoic acids (CDA), and polar compounds contents, and p-anisidine values (PAV). Phospholipid (PL) classes were determined by high performance liquid chromatography. PL was not detected in frying oil and fried products without egg yolk, while the first batch of fried products added with egg yolk at 3.53, 6.73, and 9.66 in 100 g of the dough contained total PL at 3.73, 7.93, and 8.98 mg/g, respectively. Contents of PL classes tended to increase in the products fried in the oil performing more fryings. As the number of fryings of oil increased, FFA, CDA, and polar compounds contents and PAV of frying oil increased. Addition of egg yolk to the dough significantly decreased CDA and polar compounds contents and PAV of frying oil, but it increased FFA values. Lipid of fried products showed the same tendency in CDA contents and PAV. The results clearly indicate that egg yolk powder improved the oxidative stability of frying oil during frying, possibly due to PL.     

藜麦粉对冷冻面团特性及其面包品质的影响

将藜麦和小麦粉按一定比例混合,用快速粘度分析法测定混合粉糊化特性,流变仪测定了冻藏过程中小麦-藜麦冷冻面团的流变学特性,核磁共振法测定面团中水分迁移,并测定其发酵体积变化,最后分析了冷冻面团组织状态与产品品质的关系。结果表明：藜麦粉对冷冻面团及面包的品质均有改善。藜麦粉降低了混合粉体系的糊化粘度和崩解值。冻藏后,冷冻面团的弹性模量和粘性模量增加,小麦粉冷冻面团损耗角正切值增加了4.73%,添加量为5%时冷冻面团损耗角正切值仅增加0.41%;小麦冷冻面团自由水上升了3.90%,藜麦添加后仅上升2.40%,可见藜麦粉能冷冻面团降低水分迁移程度;同时,添加藜麦粉能维持面团面筋网络结构的完整性,发酵体积由26.42 mL/h增大到29.17 mL/h。不同添加量的藜麦粉对面团及面包的品质改善程度不同,最适添加量为10%,烘烤后面包比容为3.08 mL/g,硬度为2803.48 g。本研究可为开发藜麦冷冻面团提供理论基础,在藜麦新产品开发方面具有重要的指导意义。     

不同竹笋粉添加量的面团特性及面包品质的变化

竹笋含有丰富的营养成分。为了探讨竹笋粉对面团和面包品质影响,该研究把竹笋粉以不同添加量（0%、3%、5%、7%,m/m）加入到小麦粉中制作成面包,对面团面筋蛋白、面包色泽、感官、质构特性和贮藏性进行测定。结果表明：随着竹笋粉添加量的增加,面团面筋蛋白含量降低,面包硬度和咀嚼性均提高。低剂量竹笋粉的添加（3%~5%）对面团的pH值和面筋含量影响不显著（P>0.05）,但添加量为7%时湿面筋含量相对下降了9.87%,影响显著。竹笋粉添加与面包的比容和失水率呈负相关,空白组、添加量3%、5%、7%（m/m）的失水率分别为2.45%、2.09%、2.17%、1.77%,其硬度、胶着性、弹性以及咀嚼性变化显著（P<0.05）,对内聚性、回复性影响不显著（P>0.05）。添加竹笋粉（3%~5%）可以提升面包的色泽,使面包具清香风味,但7%的添加量使面包的色泽过深,气味较浓。说明低剂量（3%~5%）的竹笋粉添加制备面包,可提升面包咀嚼感,亮色、丰富其营养成分,还起到延缓面包老化作用。     

Changes in glyoxal and methylglyoxal content in the fried dough twist during frying and storage

Glyoxal (GO) and methylglyoxal (MGO) are important precursors for advanced glycation end products (AGEs) in foods and in vivo, which are also known as reactive carbonyls. Accumulation of AGEs may result in health risk. The effect of frying time and temperature on GO and MGO formation during fried dough twist processing was investigated. The changes in GO and MGO content of fried dough twist were also examined under the different storage condition. Sample extraction, derivatization, and cleanup conditions were evaluated to provide a sample preparation method for GO and MGO analysis by RP-HPLC–DAD. Quantification limits of GO and MGO were 0.01 and 0.02 mg/L for fried dough twist, respectively. The average recovery rate was 89 % with detection relative standard deviation of lower than 5.7 %. During frying and prolonged storage, GO and MGO contents in fried dough twist ranged from 6.5 to 11.8 mg/kg and from 5.1 to 12.0 mg/kg, respectively. The results indicated that content of GO and MGO in fried dough twist depended on the frying time and temperature. For GO, no significant differences (p < 0.05) among the all types of samples were found during the whole process of storage, with the exception of storage temperature after 60-day storage. Changes in MGO occurred during the 60-day storage, indicating storage temperature, oxygen content, lighting, and storage duration, exert a significant effect on the development of the MGO.     

Flavor and Storage Stability of Potato Chips Fried in Cottonseed and Sunflower Oils and Palm Olein/Sunflower Oil Blends

ABSTRACT: Potato chips fried in cottonseed (CSO) and sunflower (SFO) oils and 20 and 40% palm olein oil (POO):SFO blends were stored at 23 to 25 °C for 0-, 3- and 6-wk in dark (DS) and in 1.5-1.7 footcandles of light (LS). During DS, peroxide values (PV) increased only in chips fried in SFO. In LS, PV increased at lower rates in chips fried in POO blends than in CSO or SFO. Sensory evaluation showed potato chip flavor intensity was similar among oils/blends and unchanged during storage, but intensities of oxidative rancidity and off-flavor increased in chips fried in CSO at 6-wk LS. This off-flavor most likely was due to 1-decyne identified by SPME analysis. Addition of POO to SFO improved the stability of chips as measured by PV without sacrificing potato chip flavor.     

Effect of Alkali Dipping on Dough and Final Product Quality

ABSTRACT: The effects of alkali dipping on starch, protein, and color changes in hard pretzel products have never been researched. Experiments were conducted to mimic reactions occurring on the pretzel dough surface. Dough was dipped in water or 1% sodium hydroxide solution at different temperatures between 50°C and 80°C. Protein and starch profile after dipping were analyzed. Color development on pretzel surface following the extraction of pigments from flour was investigated. Whole dough and pretzel samples were also made at pilot plant and the properties were analyzed. Only starch granules on the dough surface were gelatinized following dipping. Amylose-lipid complex dissociated at a lower temperature with alkali treatment but were not dissociated, even at high-temperature dipping in water. Treating the dough at 80°C in alkali solution resulted in the hydrolysis of proteins into smaller peptides that could be not precipitated by trichloroacetic acid (TCA). Dough surface color was different following pigment extraction from flour but not significantly different following baking. The results suggest that the color that developed on pretzel surface was not due to pigments present in the flour but was contributed by the reaction within or between the starch and protein hydrolysis derivatives during baking.     

Effect of tertiarybutylhydroquinone on lipid oxidation in fish crackers

The effect of tertiarybutylhydroquinone (TBHQ) in retarding lipid oxidation in fish crackers fried in refined, bleached and deodorised palm olein (RBD olein) during storage was evaluated. The indices of lipid oxidation used were the peroxide and p-anisidine values and u.v. absorbances at 232 and 268 nm of oil extracted from fish crackers stored at 60°C. Two methods for TBHQ incorporation into the fish crackers were used. Fish crackers that were prepared by frying of fish chips in RBD olein containing TBHQ were more stable towards oxidative rancidity than control fish crackers prepared with RBD olein without TBHQ. The rate of lipid oxidation in fish crackers prepared from fish chips that were made with TBHQ in the dough formulation and fried in RBD olein without TBHQ was slightly higher than in control fish crackers. A storage study carried out at room temperature (30°C) showed the same trend in relative rates of lipid oxidation. The study showed that the incorporation of TBHQ into the frying medium was an effective means of retarding the onset of rancidity in fried fish crackers while the incorporation of TBHQ into the dough mixture made the fish cracker slightly more susceptible towards lipid oxidative reactions.     

黄秋葵全粉对小麦面团流变学特性的影响

为了探究黄秋葵全粉对小麦面团流变学特性的影响,采用Mixolab混合实验仪、吹泡仪、流变发酵仪以及旋转流变仪等技术手段研究了混合粉（黄秋葵全粉添加量为0、1%、3%、5%、7%、9%）面团的热机械学特性、吹泡特性、流变发酵特性以及动态流变学特性。结果表明,随黄秋葵全粉添加量的增加,混合粉湿面筋含量降低,减少幅度达79.96%;面团的吸水率由63.30%增加到65.90%,形成时间和稳定时间先下降后上升,蛋白质弱化度增强;面团的蒸煮稳定性没有发生变化,但糊化峰值粘度下降,回生值减小;面团的韧性、延展性以及发酵性能下降,最大发酵高度Hm值下降了39.80%。此外,面团的储能模量G'和损耗模量G'均显著增加（P<0.05）,且G'增加占主导地位。综上所述,黄秋葵全粉的添加显著改变了小麦面团的流变学特性,且各添加量下混合粉面团的流变学特性指标有差异。研究结果为黄秋葵复合面制品的开发提供了理论依据。     

三种甘油酯对冷冻面团及其面包品质的对比分析

本文通过核磁共振测定冷冻面团及其面包的水分迁移情况,流变仪测定冻藏过程中冷冻面团的流变学特性,质构仪和扫描仪分析面包的品质,研究三种甘油酯:乙酰化单、双甘油脂肪酸酯(ACETEM),双乙酰酒石酸单双甘油酯(DATEM)和六聚甘油单油酸酯,对冷冻面团及其面包品质的影响。结果表明:在冻藏过程中,三种甘油酯对冷冻面团及其面包的品质均有改善。与对照组相比,冻藏前三种甘油酯增加了面团及其面包的结合水比例,分别是面团增加了4.21%、7.02%、11.23%和面包增加了0.27%、4.67%、16.00%。而冻藏后,三种甘油酯降低了冷冻面团及其面包的水分迁移。在冻藏期间,冷冻面团的粘弹性降低,它们的损耗角正切值(tanδ)增加,发酵后对照组面团的tanδ增加了11.90%,添加了0.5%ACETEM面团的tanδ仅增加了4.76%。冻藏60d后,含0.5%ACETEM的面包比容为3.29m L/g,比对照组增大了23.50%;面包硬度为2298.92g,比对照组柔软19.18%。因此,添加了0.5%ACETEM的改善效果最好。     

冷冻华夫面团保质期内品质提升的研究

研究了冷冻华夫面团冻藏期间的水分质量分数、水分分布、酵母含量、产气能力、持气能力等指标的变化,阐明冷冻面团品质变化的机制。实验表明,冷冻华夫面团冻藏时间对产品品质具有显著影响,当冻藏时间为3个月时,酵母含量、产气能力、持气能力分别下降了28%、23%和36%。通过研究不同类型添加剂(谷朊粉、黄原胶、羟丙基甲基纤维素、结冷胶)对冷冻面团冻藏期间品质的影响,发现适量加入添加剂对于产品品质的提升具有一定效果,其中谷朊粉和黄原胶在降低冰晶体机械损伤、提高面团发酵能力方面效果显著。与对照相比,谷朊粉提升酵母含量131%,发酵能力210%,黄原胶提升酵母含量107%,发酵能力181%。     

桑叶超微粉对小麦面团粉质特性及馒头品质的影响

用桑叶超微粉替代部分小麦粉（5%、10%、15%、20%、25%）制作馒头,研究了桑叶超微粉对小麦面团粉质特性和馒头品质的影响。结果表明：桑叶超微粉可提高面团吸水率,面团稳定性呈现先增加后降低的趋势;当取代比例超过15%时,面团的稳定时间显著降低、弱化度显著增加。馒头品质研究结果表明,随着桑叶超微粉添加量的增加,馒头的比容逐渐下降,高径比呈现先增加后降低的趋势,馒头硬度和黏着性增加。当桑叶超微粉添加量为15%时,桑叶馒头的颜色为青绿色,感官评价较高。老化实验结果表明,桑叶超微粉降低了馒头硬化速率,可有效延缓贮藏期间馒头的老化。综上,15%的桑叶超微粉馒头具有较高的感官整体接受性,品质最佳。     

Influence of Low-temperature Blanching Combined with High-pressure Shift Freezing on the Texture of Frozen Carrots

ABSTRACT: Freezing causes texture loss of tissue-based systems such as fruits and vegetables. To evaluate the potentials of high-pressure freezing for minimizing freezing damage, the effects of high-pressure shift freezing and regular freezing conditions on the texture of carrot cylinders were investigated. To improve the strength of the plant material by a pectin-based network, carrot cylinders were submitted to different pretreatment conditions before freezing. The reduced freezing time of high-pressure shift freezing compared with conventional freezing results in a limited positive effect on the hardness of non-pretreated carrots. A pronounced hardness improvement was obtained when calcium soaking followed by thermal (30 min at 60°C) or high-pressure (15 min at 60°C and 300 MPa) pretreatment was combined with high-pressure shift freezing. During subsequent frozen storage at -18°C, the increased hardness values of pretreated, high-pressure frozen carrots could not be maintained.