Prediction of moisture content in steamed and dried purple sweet potato using hyperspectral imaging analysis

Food Science and Biotechnology - Partial least squares regression (PLSR) modeling was performed to predict the moisture content in steamed, dried purple sweet potato based on spectral data obtained...     

薯片的感官描述分析

薯片是一种喜闻乐见的休闲类小食品,尤其得到青少年消费者的青睐。而产品的销售数量会受到感官特性的影响,比如薯片的脆度,硬度,薄厚等。在本次调研中,通过感官描述分析,首先筛选出9种不同味道薯片,并对18名在校生评定员进行培训,对每个感官描述词汇进行定义和标准样品的选择,得到一个28个感官描述词汇表,最后生成薯片的感官描述分析图。 本文是感官分析在大专院校科研技术平台应用的一个典范,通过科学、系统的建立一个特定产品的感官评定小组（招募、筛选、培训和感官能力评估）,产生感官描述词汇、定义和参照物评分原则,建立产品的感官属性图谱,从而达到感官属性定性定量的目的。     

Analysis of potato chips using FTIR photoacoustic spectroscopy

The suitability of Fourier transform infrared photoacoustic spectroscopy (FTIR‐PAS) for analysing potato chips was investigated. The functional groups, vibration modes and intensities corresponding to frequencies related to moisture, fat and protein in PA spectra were labelled. Oxidation experiments were carried out by heating home‐made chips in a convection oven at 80 °C. Changes in chemical groups related to fat and oil were observed visually and statistically. Spectral data were analysed using PCA correlation and a linear discriminant analysis technique with squared Mahalanobis distance metric to estimate the extent of oxidation. Results showed that deterioration indeed could be monitored by photoacoustic spectroscopy. Depth profile analysis of the samples showed that a spectral difference in the fat, moisture and protein bands at different layers exists. Results demonstrated that FTIR‐PAS with its depth‐profiling capability could be used for qualitative analysis. © 2000 Society of Chemical Industry     

Determination of consumer acceptance limits to sensory defects using survival analysis

Survival analysis concepts and calculations were applied to consumers' acceptance/rejection data of samples with different levels of sensory defects. The following defects in UHT milk were studied: acid, caramel, cooked, dark color, lipolytic and oxidized. For each defect a series of nine concentrations were prepared and tested by 50 member consumer panels. The lognormal parametric model was found adequate for most defects and allowed prediction of concentration values corresponding to 10% probability of consumer rejection. For cooked flavor the model was not adequate due to a large number of right censored data, consumers did not find this defect objectionable. For oxidized flavor there were also many right censored values, but this was due to an inadequate concentration range.     

Texture measurement of potato chips using a novel analysis technique for acoustic vibration measurements

The texture of potato chips was evaluated using a novel method. Four kinds of potato chips with different thicknesses and crispness were fractured by a probe and the corresponding acoustic vibrations were detected by a piezoelectric sensor. The vibration signals were filtered into 19 frequency bands. The texture index (TI) was calculated for each band, using data from three selected parts of the time-domain signals: the anterior part from the probe contact point to a major fracture, the major fracture part, and the full texture signals. The TI was the lowest for the anterior part at all bands. The TI of the major fracture part was the highest in all frequency bands except for 100–140 Hz. The new analysis method revealed that the TI above 1600 Hz reflected the crispness of potato chips.     

Estimation of crispness and consumer acceptance of fried potato chips by mechanical and acoustic measurements

Fried potato chips retaining various moisture contents (MCs) (2.21–9.20%) were analysed to estimate the intensity of crispness and consumer acceptance by texture and acoustic measurements. The MC of the chips was highly correlated with the mechanical maximum force (MMF) in the texture measurement, total area (MTA) and number of sound peaks (NSP) in the acoustic measurement. The intensities of crispness and consumer acceptance decreased as the MC of potato chips increased. For the predictive models established, the combined use of mechanical and acoustic parameters was shown to better predict sensory crispness intensity [R² = 0.975, root mean square error of prediction (RMSEP) = 0.138] and consumer overall liking (R² = 0.966, RMSEP = 0.111) than either parameter alone. Based on the instrumental‐sensory crispness equivalent table established, the estimated values of the MTA were below 71.24, while the NSP should be above 22.81 to meet ‘slightly like’ category of consumer acceptance.     

Physicochemical, mechanical and thermal properties of brown rice grain with various moisture contents

The effects of moisture content on the mechanical and thermal properties of either a short‐grain variety (Akitakomachi) or two long‐grain varieties (Delta and L201) of brown rice were studied. Total starch contents of the three varieties were comparable, but the amylose content of L201 was significantly higher than that of the other two varieties. The maximum compressive strength of brown rice grain was much higher than the maximum tensile strength. L201 showed the highest maximum compressive and tensile strengths. The phase transition temperatures (glass transition temperature T_g and melting temperature T_m) were examined by differential scanning calorimetry. The T_g and T_m for L201 were higher than those for Delta and Akitakomachi. The maximum compressive strength, maximum tensile strength, T_g and T_m for the three varieties of brown rice grains decreased with increasing moisture content. The T_g of individual brown rice kernels decreased from 53 to 22 °C as moisture content increased from 12 to 25% wet basis. A statistical model was calculated by using linear regression to describe the change in T_g in terms of moisture content.     

Experimental determination of thermal conductivity of apple and potato at different moisture contents

Thermal conductivity of apple and potato samples was measured by means of a specifically designed apparatus based on Fitch's method. The thermal conductivity was determined at various moisture contents at the sample mean temperature of 30 °C. As expected the conductivity decreases with the decrease in moisture content. Thermal conductivity data were correlated with moisture content using a straight line.     

On-line monitoring of fat,dry matter and acrylamide contents in potato chips using near infrared interactance and visual reflectance imaging

The contents of dry matter, oil and acrylamide are some of the most relevant parameters in the quality control of potato chips. Near infrared spectroscopy (NIR) is a common technique for routine analysis of bulk chemistry in different raw materials and products because it allows a fast and non-destructive analysis of samples. The objective of this research was to investigate the possibilities of using on-line NIR monitoring of acrylamide, moisture and oil content in potato chips. Sixty samples of potato chips from individual frying runs were measured on-line using a VIS/NIR interactance line scanner. The same samples were analysed in the laboratory to determine their corresponding moisture, acrylamide and oil contents. The mean VIS and NIR spectra for the 60 samples were modelled against the reference values for acrylamide, fat and dry matter using partial least squares regression (PLSR), and the regression models were validated using full cross-validation. On-line NIR interactance was found to predict fat and dry matter of potato chips with high accuracy, i.e. prediction errors of 0.99 and 0.86% (w/w), respectively. The corresponding correlations between predicted values and reference values were 0.99 and 0.97 for fat and dry matter. For acrylamide an average prediction error of 266 μg/kg was achieved using NIR and VIS signals in combination. The correlation between predicted values and reference values was 0.83 for this model. The system may be used to separate samples with very high acrylamide contents from samples with average to low contents.     

Acrylamide reduction in potato chips by using commercial asparaginase in combination with conventional blanching

In this research acrylamide reduction in potato chips was investigated in relation to blanching and asparaginase immersion treatments before final frying. Potatoes slices (Verdi variety, diameter: 40 mm, thickness: 2.0 mm) were fried at 170 °C for 5 min (final moisture content of ∼2.0 g/100 g). Prior to frying, potato slices were treated in one of the following ways: (i) Rinsing in distilled water (control I); (ii) Rinsing in distilled water plus blanching in hot water at 85 °C for 3.5 min; (iii) Rinsing in distilled water plus immersion in an asparaginase solution (10000 ASNU/L) at 50 °C for 20 min; (iv) Rinsing in distilled water plus blanching in hot water at 85 °C for 3.5 min plus immersion in an asparaginase solution (10000 ASNU/L) at 50 °C for 20 min; (v) Rinsing in distilled water plus blanching in hot water at 85 °C for 3.5 min plus immersion in distilled water at 50 °C for 20 min (control II). Blanching in hot water (ii) was almost as effective as asparaginase potato immersion (iii) in order to diminish acrylamide formation in potato chips (acrylamide reduction was ∼17% of the initial acrylamide concentration). When potato slices were blanched before asparaginase immersion, the acrylamide content of the resultant potato chips was reduced considerably by almost 90%. We have demonstrated that blanching of potato slices plus asparaginase treatment is an effective combination for acrylamide mitigation during frying. It seems to be that blanching provokes changes in the microstructure of potato tissue leading to an easier and more effective diffusion of asparaginase.     

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.

     

Colour and image texture analysis in classification of commercial potato chips

The images of commercial potato chips were evaluated for various colour and textural features to characterize and classify the appearance and to model the quality preferences of a group of consumers. Features derived from the image texture contained better information than colour features to discriminate both the quality categories of chips and consumers’ preferences. Entropy of a¹ and V and energy of b¹ from images of the total chip surface, average and variance of H and correlation of V from the images of spots and/or defects (if they are present), and average of L¹ from clean images (chips free of spots and/or defects) showed the best correspondence with the four proposed appearance quality groups (A: ‘pale chips’, B: ‘slightly dark chips’, C: ‘chips with brown spots’, and D: ‘chips with natural defects’), giving classification rates of 95.8% for training data and 90% for validation data when linear discriminant analysis (LDA) was used as a selection criterion. The inclusion of independent colour and textural features from images of brown spots and/or defects and their clean regions of chips improved the resolution of the classification model and in particular to predict ‘chips with natural defects’. Consumers’ preferences showed that in spite of the ‘moderate’ agreement among raters (Kappa-value = 0.51), textural features have potential to model consumer behaviour in the respect of visual preferences of potato chips. A stepwise logistic regression model was able to explain 86.2% of the preferences variability when classified into acceptable and non-acceptable chips.     

The fluidization characteristics of potato chips

The fluidization characteristics of potato chips and potato cuboids have been investigated and the results compared with correlations obtained for the fluidization of plastic cuboids.
It was found that potato chips and cuboids behaved in a similar manner to the plastic cuboids and that the plastic cuboid correlations may be used to predict the performance of potato chips and cuboids.
Certain fluidization parameters may be used to predict the minimum transportation velocity of potato chips in vertical pipelines.     

膨化马铃薯片的生产工艺研究

本文以新鲜马铃薯和玉米淀粉的主要原料,从原料的配比,老化条件的测定等方面对一种即食马铃薯酥片的生产工艺进行了实验研究,通过实验研究初步确定了产品的生产工艺、主要工艺条件及配方。以本工艺生产的产品具有香酥脆的特点。该产品的开发与马铃薯资源的深加工利用提供了一条新途径。     

Keeping qualities of potato chips flavoured with kebab and salt

The volatile components from kebab flavour used in dusting potato chips were isolated by continuous steam distillation extraction (SDE) method. Sixteen volatile components were identified by gas chromatography-mass spectrometry (GC-MS) technique. The main constituents were aldehydes, hydrocarbons, thiophenes and fatty acids. Two potato chips samples, one flavoured with salt and the other with the kebab flavour, were stored for six months at room temperature. The aroma of each sample was isolated before and after storage. The results showed that the most contributor components to potato chips aroma were decreased by storage while the components which are responsible for rancid flavour were increased in the two samples, but with better results for the sample flavoured with salt.     

Enzymatic mitigation of acrylamide in fried potato chips using asparaginase from Aspergillus terreus

Acrylamide in foods is declared as carcinogen. In the present work, the effect of enzymatic pretreatment and other parameters like enzyme concentration, frying conditions with respect to temperature and time, size of potato chips, and effect of sodium chloride and citric acid on mitigation of acrylamide were studied. The concentration of acrylamide in fried potatoes after the pretreatment was found to be 815.63 μg kg^?1. The optimised asparaginase concentration for the mitigation of acrylamide was calibrated as 4 U mL^?1, and optimised frying time and temperature were 15 min and 170 °C, respectively. An in‐depth kinetic relationship for the effect of asparaginase on the mitigation of acrylamide was studied. The prime novelty of the project is focused on the immobilisation of asparaginase to nanomagnetic particles for redundant usage with stabilised enzyme activity. The work projected three stables cycles of asparaginase activity and on further usage of the immobilised enzyme resulted in decreased activity. The repeated use of immobilised asparaginase provides the advantage of decreasing cost in processing.     

Production of conjugated linoleic acid-rich potato chips

ABSTRACT:  Conjugated linoleic acid (CLA) is found primarily in diary and beef products, but the health benefits of CLA can only be realized if they are consumed at much greater levels than a normal healthy dietary intake. We have recently shown that a CLA-rich soy oil can be produced by simple isomerization of linoleic acid in soy oil by photoirradiation. This oil may allow greatly increased dietary CLA without significantly elevating fat intake. The objective of this study was to prepare CLA-rich potato chips by frying in CLA-rich soy oil. Soy oil was photoisomerized in the presence of iodine catalyst with UV/visible light. The irradiated oil was clay processed to remove the residual iodine and this oil was then used to fry potato chips. Oil was extracted from fried chips and analyzed for its CLA content with gas chromatography. A 1-oz serving of CLA-rich potato chips contained approximately 2.4 g CLA as compared to 0.1 g CLA in 3-oz serving of steak fillet and 0.06 g CLA in 8-oz serving of whole milk. The peroxide value of the oil extracted from potato chips was found to be 1 meq/1000 g sample, which was within the acceptable commercial standards. This study may lead to the commercialization of CLA-rich food products.