减少高温加工食品中丙烯酰胺含量的几种方法

原料中还原糖、天冬酰胺含量及加工温度是影响食品中丙烯酰胺形成的主要因素。减少原料中的还原糖或天冬酰胺含量及降低加工温度能显著降低食品中丙烯酰胺的含量。本文概述了几种减少高温加工食品中丙烯酰胺含量方法的研究进展。     

果糖/天冬酰胺模拟体系中丙烯酰胺产生机理的研究

系统研究了果糖/天冬酰胺模拟体系中丙烯酰胺形成规律。在单因素实验的基础上,选取加热温度、加热时间、天冬酰胺添加量、果糖加入量4个因素,进行响应面优化分析。结果表明:果糖的添加量、加热温度和天冬酰胺的添加量对丙烯酰胺的产生影响显著。丙烯酰胺最大产生量的条件为:加热温度200℃,加热时间6.0 min,果糖添加量1.2 mmol,天冬酰胺添加量1.2 mmol。丙烯酰胺的生成量为1640.0 nmol。     

黑蒜发酵过程中还原糖和可溶性糖含量变化的研究

采用2个发酵工艺对市售的3种大蒜进行黑蒜发酵,研究黑蒜发酵过程中还原糖和可溶性糖含量的变化。实验结果表明:发酵时大蒜中还原糖和可溶性糖均呈现先上升后下降的趋势,其中发酵工艺一时,还原糖和可溶性糖含量最高值花蒜分别为49.36、43.57 g/100 g,白皮蒜分别为32.84、40.16 g/100 g,独瓣蒜分别为47.27、41.90 g/100 g;发酵工艺二时,还原糖和可溶性糖含量最高值花蒜分别为17.01、38.05 g/100 g,白皮蒜分别为24.27、37.74 g/100 g,独瓣蒜分别为20.91、37.42 g/100 g。     

果汁饮料中还原糖快速测定技术的研究

采用还原糖测定仪法和手工斐林试剂法测定果汁饮料中的还原糖含量。结果表明,还原糖测定仪法标准偏差、变异系数均小于直接滴定法,其回收率为98.4%。说明采用还原糖测定仪法测定,数据的稳定性好,重现性好,测定结果的精密度好,准确度高,是目前测定果汁饮料中还原糖含量的一种理想方法。     

果蔬及其制品中可溶性总糖和还原糖的测定方法评价

果蔬及其制品中可溶性总糖和还原糖是其质量指标的重要参数之一。综述了可溶性总糖和还原糖的不同测定方法的适用性及特点。由于不同果蔬的可溶性总糖和还原糖的含量有较大差异,综述的测定方法为果蔬可溶性总糖和还原糖的测定提供意义及借鉴。     

制糖过程中还原糖问题的初步研究

本文根据实验研究结果与工厂查定资料,论述了制糖过程中影响还原糖分解的主要因素及这种分解对生产过程和经济效益的严重影响。作者呼吁广大糖厂(尤其是甘蔗含还原糖高的厂)树立还原糖也是糖的思想,并提倡“中性偏微酸”和“宁酸而勿偏碱”的澄清工艺条件。     

粮食中还原糖和非还原糖测定国家标准（GB/T5513-2008）中存在问题的修改建议

在依据国标（GB/T 5513-2008）进行还原糖和非还原糖含量的测定过程中,发现该标准有些地方表达不太准确或缺乏可操作性。该文针对还原糖和非还原糖测定测定中遇到的问题,指出了该标准中的不足并提出相应的修改建议。     

糖果中还原糖的快速测定技术

采用还原糖测定仪法和手工费林试剂法两种方法测定糖果中还原糖含量。结果表明,还原糖测定仪法标准偏差(S)=0.198,变异系数(CV)=0.015,均小于手工费林试剂法,其回收率为98.8%,也高于手工费林试剂法。说明还原糖测定仪法数据稳定性好,重现性好,测定结果精密度好、准确度高。      

漫反射光谱法测定葡萄酒和蜂蜜中还原糖的研究

报道漫反射光谱法测定葡萄酒和蜂蜜中的还原糖，讨论了测定条件。该方法具有操作简便，灵敏度高（检出限为１０μｇ），试剂用量少（＜１ｍｌ）等优点。还原糖在２０～１３０μｇ范围有良好的线性关系。通过对部分实际样品的测定，结果满意。     

谷氨酸发酵中还原糖自动测定技术的研究

用谷氨酸发酵行业大多采用的手工斐林试剂法和还原糖测定仪法两种方法测定谷氨酸发酵液还原糖含量。结果表明还原糖测定仪法标准偏差(S)变异系数(CV)均小于直接滴定法，其回收率却高于直接滴定法，说明还原糖滴定仪法，数据的稳定性好，重现性好，测定结果的精密度、准确度高。     

Plasticized methylcellulose coating for reducing oil uptake in potato chips

BACKGROUND: As a result of consumers' health concerns and the trend towards healthier and low‐fat food products, research has been undertaken to reduce the amount of fat absorbed in fried foods. This work focused on studying the efficacy of sorbitol and glycerol as plasticizers of methylcellulose coatings used to reduce oil uptake during the frying process of potato chips RESULTS: Changes in color, mechanical properties, water activity and lipid oxidation during storage were monitored. Also, an explanation regarding the different performances between both methylcellulose coatings with and without plasticizer was attained and techniques from the field of packaging films such as dynamic mechanical analyzer (DMA) and Fourier transform infrared spectroscopy were applied to analyze the behavior of coatings submitted to the frying operation. The application of a methylcellulose coating was an adequate choice to reduce oil absorption in fried potato chips. The most effective formulation was 10 g L^?1 methylcellulose with the addition of 7.5 g L^?1 sorbitol. With the incorporation of this formulation, oil absorption was reduced by 30%. Neither the sorbitol concentration nor the presence of the MC coating affected the puncture maximum force and color parameters L and a*. The results of the sensory analysis indicated that the panelists could not distinguish between the coated and uncoated potato chips. CONCLUSION: Methylcellulose‐based coating plasticized with sorbitol could be an alternative for obtaining healthier potato chips. Copyright © 2011 Society of Chemical Industry     

复合马铃薯片油炸工艺研究

以马铃薯淀粉和马铃薯全粉为主要原料,对复合马铃薯片的油炸工艺参数进行了研究。采用正交试验,确定了生产低含油量、低丙烯酰胺(AA)含量、高脆度复合薯片的最佳油炸工艺参数,即油炸前坯料的含水量控制在20%左右,含盐量2%左右,油温以160℃为佳,炸制时间为40 s,油炸薯片丙烯酰胺含量为0.28 mg/kg,在市售薯片基础上降低26.32%;含油量为23.36%,降低了1.47个百分点。     

Apparent diffusivities of reducing sugars in potato strips blanched in water

The mechanism of reducing sugar losses was investigated in potatoes cut into 9.5 × 9.5 mm and 13 × 13 mm strips and blanched for 300–2400s at different temperatures between 70°C and 100°C. Experiments were carried out using large amounts of well-agitated water. Assuming no chemical reaction and using appropriate solutions of the unsteady state diffusion equation for square parallelpiped geometry, the apparent diffusivities, D_a, of reducing sugars in the potato matrix were determined at different temperatures. the incorporation of the dimensions of the strips in the solution of the diffusion equation was sufficient to explain the effect of size on losses. Values of D_a were found to be in the range 1.2 × 10^-11 1.7 × 10^-11 m²s^-1 and could be correlated with temperature according to the Arrhenius law.     

复合马铃薯食品的配方与加工工艺研究

以市售优质新鲜马铃薯为基本原料,以改善营养和突出特色风味为目的,进行复合型油炸马铃薯薯片实验的初步研究。实验中采用单因子实验和正交实验,筛选出科学的配方与合适的工艺条件,并对马铃薯和有关原料的复合应用进行探讨。     

Reduction of acrylamide formation by vanadium salt in potato French fries and chips

The effects of vanadyl sulphate on the formation of acrylamide have been studied in fried potato products, such as French fries and chips. Acrylamide formation was inhibited by 30.3%, 53.3% and 89.3% when the sliced potato strips were soaked in 0.001, 0.01 and 0.1 M vanadyl sulphate (VOSO₄) solutions, respectively, for 60 min before frying. Moreover, 57.7%, 71.4% and 92.5% inhibition of acrylamide formation was observed when chips were soaked in the respective vanadyl sulphate solution before frying. In a separate model reaction, a solution containing an equimolar concentration of l-asparagine and d-glucose showed a significant inhibition of acrylamide formation when heated at 150 °C for 30 min in the presence of vanadyl sulphate (VOSO₄). The results indicate that the binding of VO²⁺ to asparagine and the decrease in the pH of the potato samples resulted in a significant reduction of acrylamide formation in fried potato products.     

Use of the alditol acetate derivatisation for the analysis of reducing sugars in potato tubers

The alditol acetate derivatisation for determining levels of reducing sugars in ethanolic extracts from potato tubers by gas chromatography was investigated. Standard curves for alditol acetate derivatives of aqueous solutions of allose, glucose and fructose were of acceptable linearity over the concentration range of interest (R² = 0.9933, 0.9992 and 0.9997, respectively). Reproducibility of replicate derivatisation of the standards was also acceptable [mean relative standard deviation (RSD) was 5.16%]. Fructose was converted to mannitol and glucitol hexa-acetate in a fixed proportion (mean mannitol:glucitol ratio was 0.67) over the concentration range applicable to potatoes. This ratio was used to calculate reducing sugar levels in ethanolic extracts from five varieties of potatoes using allose as an internal standard. Reproducibility for replicate analyses of reducing sugars in potatoes was acceptable (Mean RSD = 6.65%) and values were within the range of those reported previously.     

Determination of salt in potato chips

Summary To have an idea about the contribution of snack foods to sodium intake, the salt contents of 39 samples of potato chips sold on the Belgian market have been determined. Therefore two methods were applied: determination of chlorides by titration and of sodium by spectroscopic methods as atomic-absorption spectrofotometry (AAS) or direct-coupled plasma emission spectral analysis (DCP). The results obtained indicate a good correlation between the different methods used. However, the salt values obtained with the AAS detection technique and with titrimetry are slightly higher than those found with the DCP spectroscopic analysis. From the total samples analyzed 40% contained more than 2% of sodium chloride.

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Bestimmung von Kochsalz in Kartoffelchips

Zusammenfassung Um eine Vorstellung zu haben, welchen Anteil Knuspernahrung (snacks) bei der Natriumaufnahme hat, wurde der Salzgehalt von 39 Proben Kartoffelchips aus dem belgischen Markt bestimmt. Hierzu haben wir zwei Methoden benutzt: Bestimmung von Chloriden durch Titration and von Natrium durch spektroscopische Methoden wie AAS and DCP. Die Resultate ergaben eine gute Korrelation zwischen den angewandten Methoden. Die Salzgehalte, die wir durch die Atomabsorptionsspektrometrie and durch Titration erhalten haben, sind jedoch ein wenig höher als die, die wir durch die Plasmaemissionsspektralanalyse gefunden haben. 40% der Proben enthalten mehr als 2% Natriumchlorid.

     

Antioxidant capacity of potato chips and snapshot trends in acrylamide content in potato chips and cereals on the Canadian market

The concentration of acrylamide was measured in selected varieties of five brands of potato chips and breakfast cereals over a 5-year period. Most of the products were purchased in one locality in Canada. Samples were analysed by an isotope dilution (¹³C₃) acrylamide method. They were extracted with water, partitioned with dichloromethane, filtered through a 5 kDa centrifuge filter, cleaned-up on HLB Oasis polymeric and Accucat mixed mode anion and cation exchange SPE columns, and analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The acrylamide concentration in potato chips varied from 106 to 4630 ng g^?1, while values in cereals varied from 50 to 347 ng g^?1. Wide variations were observed between brands, within brands over time, and between lots of the same brand. A subset of potato chip samples was analysed for in vitro antioxidant activity. No relationship was found between antioxidative capacity of potato chips and their acrylamide content.     

Factors influencing the relationships between reducing sugars and fry colour of potato tubers of cv. Record

The influence of sampling and sugar and colour assessment on the correlation between sugar content and fry colour of potatoes was investigated in cv. Record stored at 5 and 10°C (to produce a wide range of reducing sugars), and sampled at the basal, middle and apical region of the tuber.
When colour and reducing sugars from adjacent slices were compared excellent correlations were found between these two factors whether the colour was measured objectively, as reflectance density (RD) of the ground paste from fried disks (r = 0.9550) and optical density (OD) of extract from the paste (r = 0.9507), or subjectively against IBVL colour cards (r =−0.9378). Although good correlations were found for individual scorers, using matching colour cards, significantly different regression lines were found between individuals. Reducing sugar levels were generally higher at the basal end than at the apical end. Consequently, the correlations between fry colour and reducing sugars are much poorer if reducing sugar and colour are measured on different tissue in the same tuber and the variation in colour explained by variation in reducing sugar decreased from 90 to 50%.
Sampling within tubers thus appears to be a major factor determining the ability to accurately predict fry colour from reducing sugar content. It is suggested that if potatoes for processing are to be rejected on the colour of the darkest part of a tuber then a sample core for sugars should be taken from the basal region of the tuber.