氯化钙对超高压处理的鲜切马铃薯硬度改善效果的研究

超高压（Ultra-high pressure,HPP）会造成鲜切马铃薯硬度的下降,为探究氯化钙对HPP处理的鲜切马铃薯硬度的改善效果,以鲜切马铃薯为原料,在不同氯化钙处理浓度、时间和浸泡方式下对HPP处理的鲜切马铃薯硬度的变化进行研究。结果表明：氯化钙真空浸渍硬度改善效果优于普通浸泡;在此基础上,采用响应面试验对氯化钙的改善效果进行优化分析得出不同浓度氯化钙及不同真空浸渍时间与不同超高压压力、压力作用时间作用于鲜切马铃薯是交互影响的,且氯化钙溶液浓度对鲜切马铃薯的质地影响最大。在HPP压力为300 MPa,作用时间10 min结合1.0%CaCl2,真空浸渍10 min 的处理条件下,鲜切马铃薯硬度值最大,为3284.83g,与未处理的鲜切马铃薯硬度相当,钙离子含量最高,为3157.82 ug/g,显著高于未处理组钙离子含量。     

即食潮式甘草番石榴软罐头工艺研究

以番石榴为原料,优选了潮式甘草番石榴软罐头的制作工艺参数。以氯化钙为硬化剂,抗坏血酸为护色剂,研究两者不同浓度及作用时间对样品硬度、色差及口感的影响。优选的硬化护色参数为氯化钙浓度为0.2%、抗坏血酸浓度为0.4%、浸泡时间为2h。比较了果蔬软罐头杀菌中常用的巴氏杀菌、常压沸水杀菌、微波杀菌及微波-沸水联合杀菌的杀菌效果,优选的杀菌条件为微波-沸水联合杀菌:1300w微波杀菌1min后沸水浴5min,处理后的样品细菌总数检验、霉菌酵母检验及商业无菌检验均达到要求,并且ΔE值低,色差变化小,理想硬度偏离率ΔH也在可接受范围内。表明微波-沸水联合杀菌是适合潮式甘草番石榴软罐头生产的杀菌方式。     

紫色马铃薯薯条生产工艺的研究

以紫色马铃薯为原料,对丙烯酰胺含量低,色素保留较好的紫色马铃薯薯条生产工艺进行研究,得到最佳工艺为烫漂处理+微波真空冷冻。烫漂处理中最优护色剂组合为L-半胱氨酸浓度0.08%、柠檬酸浓度0.1%、氯化钙浓度125×10-6g/mL,浸泡时间10min;最佳烫漂温度70℃;烫漂时间5min。该工艺成品中未检出丙烯酰胺,色泽(E值)可降低到92.8739±5.3234。     

不同预加工方式对马铃薯片中丙烯酰胺的影响

研究不同预加工方式对油炸马铃薯片中丙烯酰胺生成的影响,进而探讨一种可有效抑制马铃薯片中丙烯酰胺含量的方法。将马铃薯片在不同温度（120℃ ～200℃）及不同时间（0 ～30 min）下进行油炸处理,通过品质指标及丙烯酰胺含量的变化趋势确定最佳油炸时间及温度,利用高效液相色谱法测定经热烫和添加剂浸泡后马铃薯片中丙烯酰胺的含量,并计算丙烯酰胺抑制率。在未进行预处理条件下,随着油炸时间及油炸温度的增大,质量损失率、色差呈整体上升趋势,水分活度、水分含量及还原糖含量呈整体下降的趋势,丙烯酰胺含量呈先上升后下降的趋势;在油炸前进行不同预处理对马铃薯片中的丙烯酰胺具有显著抑制作用,90℃热烫处理协同5 g/L半胱氨酸溶液浸泡处理10 min对马铃薯片中丙烯酰胺的抑制率达到了100%。因此,热烫协同半胱氨酸溶液浸泡处理是一种可有效抑制马铃薯片中丙烯酰胺含量的方法。     

预处理对云南脆皮薯条中丙烯酰胺形成的抑制效果研究

目的探究预处理对云南脆皮薯条中丙烯酰胺形成的抑制效果。方法通过选取油炸温度、油炸时间和淀粉水溶液浓度的3个梯度设计单因素实验,对其品质变化进行测定以及感官综合评分法评定,建立云南脆皮薯条的最佳加工工艺。为有效控制丙烯酰胺,在热加工前,将马铃薯分别进行热烫(85℃下热烫10 min)、半胱氨酸浸泡(常温下于3 g/L的半胱氨酸溶液中浸泡10 min)、热烫+半胱氨酸浸泡(在85℃下浸泡于3g/L半胱氨酸溶液中10min)预处理,以未处理为对照组。热加工后,分别对云南脆皮薯条样品的风味品质指标:水分含量、水分活度、质量、颜色、还原糖含量、天冬酰胺、半胱氨酸等进行测定,分析不同预处理方式对云南脆皮薯条风味品质的影响,并对丙烯酰胺含量进行测定,比较3种预处理方式对云南脆皮薯条中丙烯酰胺的抑制情况。结果用热烫+半胱氨酸浸泡的预处理方式处理马铃薯后制作云南脆皮薯条,水分含量、颜色、还原糖、天冬酰胺与未处理组相比没有统计学差异(P0.05);半胱氨酸含量与其他预处理组对比显著增加;丙烯酰胺含量与单独热烫、未处理组相比明显减少(P0.05)。结论运用半胱氨酸溶液浸泡并联热烫预处理云南脆皮薯条能有效降低食物中的丙烯酰胺同时保留食物风味品质。     

浸泡保脆工艺的优化对老山芹解冻后品质的影响

为探究浸泡保脆工艺对老山芹解冻后品质的影响,本试验以老山芹为原料,以溶出钙量及脆度和咀嚼性为指标,从六种保脆剂中筛选保脆剂,对样品进行低温热浸泡保脆处理,并以保脆剂复配比例、保脆剂浓度、浸泡时间为考察因素,采用响应曲面法优化浸泡保脆工艺条件。结果表明,最适合老山芹的保脆剂为海藻酸钠-氯化钙复配型保脆剂,最佳工艺条件为:保脆剂复配比1:1.8,保脆剂浓度(以浸泡液计)4 g/L,浸泡时间29 min,此时老山芹中溶出钙含量为98.93 mg/100 g,较未处理样品显著增加(P<0.05),脆度和咀嚼性也较其他条件显著提高(P<0.05),且溶出钙含量与脆度和咀嚼性呈现极显著正相关(P<0.01,相关系数0.792)。以氯化钙-海藻酸钠低温热浸泡老山芹,可有效保持其解冻后外观品质和口感。     

油炸马铃薯片中丙烯酰胺形成的协同阻断研究

目的研究油炸温度、油炸时间对马铃薯片中丙烯酰胺生成的影响,进而探讨半胱氨酸(Cys)和热烫处理对丙烯酰胺生成的协同阻断作用。方法将试样马铃薯片分别在不同浓度的Cys(0~5 g/L)溶液中,进行热烫(25~85℃)前处理,在不同温度(140~220℃)以及油炸时间(0~35 min)条件下,油炸处理,利用衍生化气相色谱-质谱联用(GC-MS)法测定样品中的丙烯酰胺含量。结果无预处理下,油炸马铃薯片中丙烯酰胺的生成量,随油炸时间或油炸温度的增加,呈先升高后降低的变化趋势,油炸温度为180℃的条件下,油炸3 min时,达到最大值5.16 mg/kg;油炸时间为5 min的条件下,油炸温度为200℃时,达到最大值4.85 mg/kg。热烫前处理对丙烯酰胺生成具有显著抑制效果,抑制率随热烫温度的升高而增大,室温条件下Cys溶液浸泡对丙烯酰胺生成具有抑制效果,抑制率随Cys浓度增加未见明显变化,然而温度升高后,出现协同阻断效应,Cys浓度为5 g/L和热烫温度为85℃的条件下,丙烯酰胺抑制率达100%。结论 Cys和热烫处理对抑制丙烯酰胺的生成存在协同阻断效应,协同作用下的抑制率与两者单独作用相比显著增加。     

采用质构仪分析氯化钙对牛肉品质的影响

CaCl2对牛肉的嫩化作用多通过感官评定,评定结果存在较多主客观影响因素.采用质构仪测定代替感官评价,测定经CaCl2处理后牛肉的食用物理特性--嫩度、硬度、弹性、胶性和咀嚼性等,可增加评定的合理性.用质构仪穿刺法和质地多面分析(TPA)试验法,对不同部位的牛肉注射不同浓度、不同量CaCl2后的品质进行分析.结果表明,使肉的综合品质较好的较优参数组合为A3、B2、C3,即牛条形腰肉注射5%的浓度为300 mmol/L的氯化钙溶液.其中牛肉的不同部位影响最大,氯化钙溶液的注射量次之,氯化钙溶液的浓度影响较小.     

不同杀菌方式对泡椒鲜切马铃薯片贮藏品质的影响

为解决泡椒鲜切马铃薯片贮藏和流通过程中出现的褐变、胀袋、质地软化等问题,采用蒸汽、微波和辐照杀菌方式对泡椒鲜切马铃薯片进行处理,通过测定L*值、硬度和感官评分,筛选各杀菌方式最优工艺参数。通过贮藏实验,对比不同杀菌方式对泡椒鲜切马铃薯片色泽、质构特性、多酚氧化酶（PPO）活性及菌落总数等指标的影响。结果表明,各杀菌方式的最优工艺参数为蒸汽杀菌时间为3 min,微波杀菌功率为700 W,辐照杀菌剂量为8 kGy。贮藏实验结果表明,辐照和微波杀菌灭酶活效果优于蒸汽杀菌,但蒸汽杀菌能更好地保持产品色泽,减缓L*值的降低,维持产品硬度、弹性和咀嚼性,菌落总数和PPO活性虽比辐照处理组和微波处理组高,但整体控制在较低水平,综合感官评分以蒸汽处理组最高。综合对比,蒸汽杀菌更适合于泡椒鲜切马铃薯片的加工。     

钙和褐变抑制剂对鲜切菠萝影响的初步研究

研究的目的是筛选对鲜切菠萝颜色和硬度有重要影响的因子。试验采用正交设计,使用浓度为0%和0.5%的异抗坏血酸钠、柠檬酸、六偏磷酸钠、EDTA和氯化钙溶液浸泡菠萝扇片3分钟,振干表面溶液后用聚苯乙烯塑料托盘装(每盘5片,每片约25g)并用PVC膜包扎密封,在10℃下贮藏7天;分别在处理后的第1天和第7天测定菠萝片的L*、a*、b*和硬度。结果表明,在α=0.05水平下,只有异抗坏血酸钠显著抑制L*、a*、b*值的变化;所有5种试剂对鲜切菠萝硬度的影响均不显著。     

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。     

Effect of soaking medium on the physicochemical properties of parboiled glutinous rice of selected Laotian cultivars

The effect of various soaking mediums, viz. water (control), 3% NaCl and 0.2% acetic acid, and without soaking on the physicochemical properties of parboiled selected glutinous (TDK8 and TDK11) and non-glutinous (Doongara) was investigated in the present study. Results showed that the chemistry of soaking had a significant effect on the head rice yield (HRY), grain hardness, crystallinity, color, pasting and thermal properties, textural attributes, and glycemic index of these rice varieties. Soaking with NaCl and acetic acid significantly increased the grain hardness and HRY than control and without soaking treatments. Acetic acid and NaCl soaking significantly affected crystalline regions of starch resulting in reduced crystallinity in X-ray diffraction analysis and thermal endotherms in DSC analysis. NaCl soaking induced swelling of starch granules resulting in high peak and final viscosities. However, acetic acid restricted swelling resulting in reduced peak and final viscosities. NaCl and acetic acid soakings also resulted in increased hardness and adhesiveness of cooked grains than normal water soaked and un-soaked parboiled rice samples. Interestingly, change in textural attributes was prominent in parboiled glutinous rice. The color difference value for fresh parboiled samples was significantly lower for acetic acid soaked samples compared to NaCl soaked and un-soaked samples probably due to bleaching effect of acetic acid. Moreover, parboiling also resulted in significant reduction in glycemic index of glutinous rice. These findings revealed the potential application of parboiling with modified soaking techniques to improve the grain quality.     

Pulsed electric fields and their impact on the diffusion characteristics of potato slices

Mass transfer in potato slices and strips after Pulsed Electric Fields (PEF) treatment was examined to evaluate potential application of PEF in potato processing. PEF treatment on cell material leads to pore formation in cell membrane and thus modifies diffusion of intra- and extracellular media. Results showed enhanced release of intracellular molecules from permeabilized tissue as well as improved uptake of low molecular substances into the sample. Sugar, one substrate for the Maillard reaction, was decreased in PEF treated potatoes, while conductivity increased after electroporation and soaking in sodium chloride solution, indicating the improved diffusion of salt caused by PEF. Higher release of cell liquid during drying of PEF treated potatoes was noticed in comparison to untreated potato slices. This effect increased with the treatment intensity. Furthermore, it was revealed that PEF application leads to a distinct reduction of fat content after deep fat frying and thus provides a potential for the production of low-fat French fries. It can be presumed that PEF is a capable assistance to thermal treatments in the processing of potato chips or French fries for the achievement of structural modifications and improved process conditions.     

盐渍海蜇皮中铝脱除的研究

海蜇是中国沿海地区重要的水产加工品之一,具有药食两用价值。由于海蜇的传统加工过程中添加了明矾,导致铝的大量残留,对食用者身体造成危害,为保证海蜇产品的安全性,需要对其进行脱铝处理。将盐渍海蜇皮分别浸泡在超纯水、pH为3.75的弱酸性电解水、0.5%的乳酸钙溶液以及0.5%的弱酸性电解水+乳酸钙复合溶液4种不同脱铝液中,并设置不同浸泡时间进行测定。结果表明：弱酸性电解水能够有效降低盐渍海蜇中的铝含量,乳酸钙溶液则可以明显缓和脱铝后海蜇硬度、弹性以及溶胀率的降低,使海蜇维持良好的感官和组织形态。得到盐渍海蜇的最佳脱铝液为0.5%的弱酸性电解水+乳酸钙复合溶液,最佳浸泡时间为3 h。该方法可有效降低盐渍海蜇皮中铝的含量,同时使海蜇保持良好的品质。     

Non-enzymatic Depolymerization of Carrot Pectin: Toward a Better Understanding of Carrot Texture During Thermal Processing

ABSTRACT Pretreated carrot discs were thermally processed (90 °C to 110 °C) in closed containers and the resulting textural characteristics were analyzed. The pretreatment conditions used include conventional high‐temperature blanching (90 °C, 4 min), low‐temperature blanching (LTB = 60 °C, 40 min), LTB combined with 0.5% calcium chloride soaking, LTB combined with 2% sodium chloride soaking, high pressure pretreatment (HP = 400 MPa, 60 °C, 15 min), HP combined with 0.5% calcium chloride soaking, and control (non‐pretreated sample). Alcohol insoluble residues (AIR) from the pretreated carrot discs were characterized in terms of degree of methoxylation (DM). The AIR samples were further subjected to fractionation into water‐soluble pectin (WSP), chelator‐soluble pectin (CSP), and sodium carbonate‐soluble pectin (NSP). Heat depolymerization patterns and β‐elimination kinetics were investigated on the different pectin fractions. Thermal texture degradation was strongly influenced by the pretreatment condition used and the processing temperature during subsequent thermal treatment. Pretreatment conditions that showed a significant reduction in DM exhibited decreased WSP content, reduced β‐elimination, and consequently superior textural characteristics. β‐elimination was markedly pronounced in the highly methoxylated WSP fractions. CSP and NSP fractions were insensitive to β‐elimination. A strong correlation (r> 0.95) between thermal texture loss of carrots and β‐elimination kinetics exists. Overall, the benefits of controlled pectinmethylesterase activity in carrot processing were pointed out.     

Effect of pre-soaking treatments on the nutritional profile and browning index of sweet potato and yam flours

The use of sweet potato and yams for product development is hindered by the discoloration from enzymatic and non-enzymatic browning. The effect of pre-soaking treatments on the nutritional changes and browning index (BI) of sweet potato and yam (greater yam and white yam) flours was investigated. Ascorbic acid (AsA), citric acid (CA), acetic acid (AA) and sodium metabisulfite (SMS) were used for soaking at three concentrations (0.25%, 0.50% and 1.00%) and two durations (1 h and 2 h). AsA and SMS removed more starch during soaking of sweet potato, while CA and AA removed more starch from greater yam and CA removed more starch from white yam. Highest removal of reducing sugars was observed in sweet potato in AA, while CA removed maximum reducing sugars from both the yams. Phenol and total free amino acid (TFA) levels were more in SMS treatment than the control sweet potato flour, and least in AA (2 h). Whilst AsA raised the phenols and TFA in greater yam, it removed phenols to the maximum in white yam. Maximum BI was in AsA treatment for the three crops, and least for flour from CA (0.25%) treated yams and AA (1.00%) treated sweet potato.Industrial RelevanceBrowning resulting from enzymatic and non-enzymatic reactions is a major drawback in the processing of sweet potato and yams for product development. The study showed that this could be successfully tackled through soaking the slices in low cost chemicals like acetic acid or citric acid and sodium metabisulfite at low concentrations. The treated slices yielded flour with very low browning indices compared to the respective native flours, which could enhance the potential of such flours in the development of food products.     

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.     

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.     

Reduction of acrylamide formation by selected agents in fried potato crisps on industrial scale

Great interest and rapid research efforts on acrylamide in foods followed an announcement in April 2002 by the Swedish National Food Authority and the University of Stockholm. Reduction of acrylamide in high-temperature processing foods, including selection of the raw material and variation of processing parameters, etc. were extensive reported. In this research, effect of some agents on acrylamide formation was investigated. A glucose-asparagines reaction model system was used to test the effect of ferulic acid, catechin, CaCl₂, NaHSO₃, and l-cysteine on inhibition of acrylamide formation and three efficient inhibitors, NaHSO₃, CaCl₂ and l-cysteine were screened. The results showed that immersing of the fresh potato chips using different concentration of the agents greatly inhibited acrylamide formation in fried potato crisps, and the efficiency increased as their concentrations increased; among them, l-cysteine is the most efficient agent but CaCl₂ is most potential. Effects of these food additives on the texture of fried potato crisps were also studied. It was found that l-cysteine showed little effect on the texture of the crisps and CaCl₂ is regarded as the suitable choice because of its low price and the acceptable mouth feel of fried crisps treated by CaCl₂, although it increased the brittleness. Moreover, the application of CaCl₂ in industrial production of fried potato crisps was also studied. In the blanching process (deactivation process of enzymes at 85 °C), a computerized electrical conductivity detector was used to keep the concentration of CaCl₂ at constant and the result showed that immersion of potato slices in CaCl₂ solution at 5 g/L reduced acrylamide formation by more than 85% in fried crisps.Industrial relevanceThis research presents a technology to inhibit acrylamide formation in fried potato chips by immersion of fresh potato chips with some food additives. The approach suggested that cysteine and calcium chloride significantly decreased the content of acrylamide in fried potato chips and their concentrations could be kept constant by using a conductor as a detector.