Relative importance of texture properties in the sensory quality and acceptance of commercial crispy products

BACKGROUND: Understanding the textural properties of a food can be important for producers and marketers of crispy products. Relationships between texture, overall sensory quality (OSQ) and consumer acceptance of different products have been a field of interest for many authors. Despite this, results of research concerning the importance of texture remain inconclusive. The aim of this study was to evaluate the relationship between texture and other sensory attributes on an example of potato chips and their OSQ and consumer acceptance. To determine which attributes played a dominant role in the OSQ of chips, statistical correlations were calculated. RESULTS: Among the 11 attributes analysed, three had a positive relationship with the OSQ. These were: fried potato odour (r = 0.487), fried potato flavour (r = 0.597) and crispness (r = 0.570). The negative relation was observed for off‐flavour notes (r = ? 0.740; ? 0.693). Among the texture attributes, also negative, but without a dominant influence on OSQ, were hardness and undesirable type of fragmentation. CONCLUSION: Texture properties were found to be significantly correlated with OSQ as well as with consumer acceptance, but other attributes, especially those with negative sensory effects, determined OSQ of the products examined and are of crucial importance for consumer acceptance. Copyright © 2008 Society of Chemical Industry     

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.     

Modeling preference of commercial toasted white corn tortilla chips using proportional odds models

Eleven commercial toasted white corn tortilla chip products from the United States were evaluated by a group of 80 consumers of age 18–35 and by a trained sensory panel. Proportional odds models in conjunction with principal components were used for internal and external preference modeling of tortilla chip consumer overall acceptance. The internal preference modeling showed that flavor was the most important attribute to consumer overall acceptance followed by the interaction of appearance by flavor and texture. The external preference modeling showed that one flavor attribute (salt aftertaste) and one texture attribute (crispness) contributed significantly to increase consumer overall acceptance, whereas one appearance attribute (instrumental color a¹) significantly lowered consumer overall acceptance. The information reported in this study is important to the tortilla chip industry to produce tortilla chips with greater consumer acceptability. This study implies that proportional odds model using principal components is an alternative tool for consumer preference modeling.     

Relationship of carrot sensory crispness with acoustic signal characteristics

The purpose of this study was to investigate the relationships of carrot sensory crispness with acoustic signal characteristics and microstructure after storage under common shelf conditions. The results showed that carrot sensory crispness declined significantly after the 14th day of storage, and the sensory score reduction was nearly up to 42% after the 28th day of storage. The carrot sensory crispness was positively related to both the waveform index (r = 0.785, P < 0.01) and sound intensity (r = 0.732, P < 0.01) of the acoustic signals in the time domain. Hilbert–Huang transform is a useful method for the observation of frequency changes in the time domain. The overall frequency bands were distributed around 200–2000 Hz through the Hilbert spectra. Rupture did not occur until the 14th day (crispness declined significantly) of storage through the scanning electron microscopy images of microstructure, and the crispness declined gradually with the increase of rupture.     

薯片断裂声学特性与硬度、脆度相关性研究

利用质构仪对薯片硬度、脆度进行断裂试验,同时收集断裂声信号进行对比分析,建立薯片酥脆度与声学特征之间的关系,对其进行物理性质的声学评级。针对3种不同薯片产品的硬度、脆度及韧性,与其断裂声音特性之间的关系进行相关性分析。结果表明:薯片脆性越大,硬度越小,韧性越小,断裂声声压级越大,但不呈线性相关。     

Effect of superheated steam prefrying treatment on the quality of potato chips

Superheated steam drying (SSD) was used as a prefrying treatment prior to deep‐fat frying for potato slices. The effect of SSD at 130, 150 or 180 °C and steam velocity of 2.0 m s^?1 on the fat uptake, colour and texture of fried potato chips was evaluated; microstructure and degree of starch gelatinization were also evaluated to help explain the fat uptake results. SSD and frying yielded potato chips with the fat content from 0.263 ± 0.002 to 0.304 ± 0.002 kg kg^?1 (d.b.), while frying without SSD led to chips with the fat content as high as 0.359 ± 0.003 kg kg^?1 (d.b.). SSD did not promote starch gelatinization. Lower fat uptake was correlated to modified surface structure and lower moisture content of potato slices prior to frying. Frying with/without SSD pretreatment yielded potato chips of similar hardness, crispness and lightness. On the other hand, SSD significantly increased redness and yellowness of the fried chips.     

Understanding potato chips crispy texture by simultaneous fracture and acoustic measurements, and sensory analysis

The fracture and acoustic properties of six commercial potato chips that differ in sensory hardness and sensory crispness were analysed and related in this work. Principal component analysis showed a correlation among the sensory attributes and the instrumental parameters (both mechanical and acoustic). Two components mainly explained the behaviour of the different potato chips. The first component was positively related to the number of force and sound events, to sound pressure level maximum, to the area under the force curve, and to sensory crispness, and negatively related to fat content; and the second component was positively related to the gradient (slope of the first part of the curve), the potato chip thickness, and to sensory hardness and sensory crispness. The behaviour of the different potato chips was explained by either one of the two components or by both components. Results indicate that certain degree of sensory hardness is necessary for higher crispness perception.     

Feasibility of non-destructive evaluation for apple crispness based on portable acoustic signal

In this paper, apple crispness was evaluated by sensory evaluation and compared with non-destructive measurements of portable acoustic signal to discuss the feasibility of non-destructive evaluation for apple crispness based on portable acoustic signal. Acoustic eigenvalues from the acoustic signal were processed by time domain and Hilbert–Huang transform (HHT), followed by analysing the correlations with apple crispness that had been evaluated via sensory evaluation. Multiple linear regression (MLR) and artificial neural network (ANN) were applied to predict apple crispness. The results proved that crispness correlates significantly (P < 0.01) with four acoustic eigenvalues, including waveform index, sound intensity, energy of low frequency and energy of high frequency. The average relative error of apple crispness predicted by ANN was 1.42 ± 1.9%, remarkably lower (P < 0.01) that of MLR (6.79 ± 5.64%), implying that the model predicted by ANN is more accurate than that of MLR.     

稻米油调和油煎炸应用研究

通过与棕榈油对比180℃下炸制薯片以及评估薯片感官喜好度、质构、口感及粘牙性等差异来评价稻米油调和油的煎炸应用性能。结果表明:采用稻米油调和油煎炸的薯片中多不饱和脂肪酸含量显著高于棕榈油(P<0.05),且其薯片的整体感官喜好度、质构口感、酥脆度、粘牙喜好度,均显著优于棕榈油薯片(P<0.05)。在加速氧化条件下,采用稻米油调和油炸制的薯片的酸价、过氧化值均与棕榈油炸制的薯片无显著性差异(P>0.05),且远低于GB 16565-2003的规定。在加速存储过程中,谷维素却得到了很好的保留。总之,稻米油调和油具有良好的煎炸性能。     

Evolution of the physicochemical properties of oil-free sweet potato chips during microwave vacuum drying

The demand for healthy and convenient foods is a worldwide trend. Sweet potato attracted great attention due to its carbohydrates with a low glycemic index. Dehydrated sweet potatoes can be an excellent alternative for using and adding value to this raw material. The objective of this study was to evaluate the physicochemical properties of sliced sweet potato during the microwave vacuum drying (MWVD) for producing crispy oil-free chips. Fresh sweet potato samples were selected, peeled, sliced, blanched, and then dehydrated using a microwave oven adapted with a vacuum chamber and a rotation system to operate under vacuum. It was measured the evolution of moisture, water activity, temperature, color, apparent specific mass, porosity, and acoustic/mechanical analysis of the texture during the MWVD. Crispy sweet potato chips were obtained in <30 min, presenting low moisture (0.028 g g⁻¹ db) and water activity (0.262). The dehydrated samples showed high porosity (67.5%) and a low apparent density (0.456 g cm⁻³). Optical micrographs and acoustic/mechanical properties showed an expanded (puffed) product structure with large pores, which resulted in irregular acoustic/mechanical signals, characteristics of a crispy food matrix. Colorimetric analyses indicated a little change between fresh and dried samples, with an absence of burnt spots. In conclusion, MWVD is a suitable process to produce highly porous sweet potato chips, adding value, and extending the vegetable's shelf life.     

Optimisation of processing variables in the preparation of sweet potato chips using response surface methodology

Models capable of predicting the product quality of sweet potato chips have been developed using response surface methodology and used to determine the optimum processing conditions. Moisture loss, oil uptake, crispness (measured using a bending-snapping test in the TA.XT2 Texture Analyser), and sensory attributes such as colour, flavour, and texture were used to assess the product quality in the preparation of sweet potato chips. The optimum conditions which were attained for maximum moisture loss (11.65% on wet basis), minimum oil uptake (2.57%), crispness (794.37 g), colour score (7), flavour score (7) and texture score (7) were: frying temperature, 174.7 °C; salt concentration, 0.45%; citric acid concentration, 0.37%; potassium metabisulphite concentration, 0.65%; and frying time, 26 s.     

Optimization of acidified warm water treatment to improve the microbiological status and sensory quality of iceberg lettuce

The optimal conditions of washing iceberg lettuce with acidified warm water to improve the hygienic and sensory product quality were determined with the aid of a central composite design. To determine the criteria of product quality, in the course of storage for 13 days at 4 °C lettuce was subjected every 2 days to sensory evaluation. The sensory values were found to correlate with the physical measurements of color (a* value) (R²=0.83) and texture (specific energy of deformation) (R²=0.77), respectively. Color, texture and overall visual quality correlated with product acceptability (R²=0.96, 0.97, 0.96, respectively). In the experiments of series I, the effect of temperature at washing (45–50 °C), pH (4–5) and treatment time (5–10 min) were investigated and the results were used for the construction of a model to describe the effects on color and texture and to define an area of sensory product acceptance. In series II the parameters were changed to ranges of temperature (45–50 °C), pH (4.6–6) and treatment time (2–5 min), and the effect on the reduction of bacterial counts within the area of product acceptance was defined. In that area reduction rates of total counts by 0.9–2.9 log cfu/g and Enterobacteriaceae by 0.8–3.0 log cfu/g were achieved. The initial germ- reducing effect was sustained until the end of storage for 7 days at 4 °C. At 50 °C, washing for 5 min at pH 4.93, the total bacteria and Enterobacteriaceae were reduced by 2.9 and 3.7 log cfu/g, respectively. The removal of the two groups of bacteria exhibited characteristic differences. Two independent experiments confirmed the reliability of the models.     

Crispness level of potato chips affects temporal dynamics of flavor perception and mastication patterns in adults of different age groups

Little attention has been paid to the texture–flavor association in solid foods, especially crisp foods. This study aimed to determine whether crispness level affects temporal dynamics of perceived intensity of three types, i.e., plain, cheese, and spicy, of flavored potato chips with respect to three age groups: younger (20–25 years), middle-aged (40–45 years), and older (65+ years) adults. While eating potato chips, participants’ mastication pattern was also assessed by electromyography (EMG). Time–Intensity analysis showed that flavors were rated more intense and maximum flavor perception occurred quicker as crispness of potato chips increased. Overall, the effect of crispness level on flavor perception was more pronounced in the older participants. The average chew strength was greater in the crisper samples and regardless of flavor type the younger participants displayed shorter chew durations than older adults. A partial least squares regression demonstrated that mastication patterns, such as the number of chews, could well predict several key temporal flavor parameters such as the maximum intensity and the area under the curve in the middle age and older age groups. In conclusion, this study extends previous research showing that textural characteristics can influence flavor perception in liquid and soft foods to crisp/brittle foods. In addition, the effect of crispness level on flavor perception varies by flavor type, age group, and mastication pattern.     

Rheological properties,ginsenosides contents,sensory evaluations of Korean red ginseng extracts

Red ginseng extracts have gained popularity due to their positive impact on health. The objective of this study was to identify the rheological properties, ginsenosides contents and sensory characteristics of six different commercial red ginseng extracts in Korea. Ginseng extracts demonstrated different shear‐thinning flow behaviour (n = 0.59–0.78) with a consistency index (K = 46.77–105.78 Pa sⁿ), which meant they had different viscosity. The amount of ginsenosides and total solid contents were highly correlated (r = 0.954). Six significant attributes (ginseng, angelica, bitterness, ginger flavour and astringency) were identified and can be used as sensory parameters for the determination of the product quality. Hedonic levels of the product were assessed by a group of ninety‐five consumers in their 20 s (n = 32) and over 30 (n = 63). Cluster analysis revealed that consumer acceptance was divided into two major clusters for those that preferred strong (n = 43) and weak (n = 42) ginseng characteristics in the extract.     

Comparative study of physical and sensory properties of pre-treated potato slices during vacuum and atmospheric frying

The objective of this research was to study the effect of different processing conditions on physical and sensory properties of potato chips. Potato slices of Desirée and Panda varieties (diameter: 30 mm; thickness: 3 mm) were pre-treated in the following ways: (i) control or unblanched slices without pre-drying; (ii) blanched slices in hot water at 85 °C for 3.5 min and air-dried at 60 °C until a final moisture content of ∼0.6 kg water/kg dry solid; (iii) control slices soaked in a 3.5 kg/m³ sodium metabisulphite solution at 20 °C for 3 min and pH adjusted to 3. Pre-treated slices were fried at 120 and 140 °C under vacuum conditions (5.37 kPa, absolute pressure) and under atmospheric pressure until they reached a final moisture content of ∼1.8 kg water/100 kg (wet basis). An experimental design (3 × 2³) was used to analyze the effect of pre-treatment, potato variety, type of frying and frying temperature over the following responses: oil content, instrumental color and texture and sensory evaluation. Vacuum frying increased significantly (p < 0.05) oil content and decreased instrumental color and textural parameters. Sensory attributes, flavor quality and overall quality, were significantly improved using vacuum frying. The higher frying temperature (140 °C) increased ΔE, maximum breaking force, hardness and crispness and decreased L^* and b^* values. On the other hand, Panda potato variety improved the color of the product. A great improvement on color parameters was obtained using sulphited potato slices instead of the other pre-treatments. Although, the better flavor was obtained for control potato chips, no significant differences were found for overall quality between control and sulphited potato chips. Significant correlations (p < 0.01) between sensory and instrumental responses were found.     

Effects of combined pretreatments on drying kinetics and quality of potato chips undergoing low-pressure superheated steam drying

Due to an increasing demand from health-conscious consumers more attention has been placed on investigating alternative techniques to replace conventional deep-fat frying to produce health-friendly snack products including potato chips. Recently, low-pressure superheated steam drying (LPSSD) has proved to have potential to produce fat-free potato chips if performed in combination with appropriate pre-drying treatments. In this study, the influences of various pretreatments and drying temperature on the LPSSD drying kinetics and quality parameters of dried potato chips were investigated. LPSSD of potato chips underwent various combined pretreatments, i.e., (a) blanching, (b) combined blanching and freezing, (c) blanching followed by immersion in glycerol solution and then freezing, and (d) combined blanching, immersion in monoglyceride solution and freezing, were carried out at different drying temperatures (70, 80, and 90 °C) at an absolute pressure of 7 kPa. The quality of the dried chips was then evaluated in terms of colors, texture (hardness, toughness and crispness) and microstructure. In terms of the drying behavior and the dried product quality, LPSSD at 90 °C with combined blanching and freezing pretreatments was proposed as the most favorable conditions for drying potato chips.     

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.     

Influence of Extrusion Cooking on In Vitro Digestibility,Physical and Sensory Properties of Brazilian Pine Seeds Flour (Araucaria Angustifolia)

Brazilian pine seeds (pinhão) are gluten‐free products derived from Araucaria angustifolia. The commercialization of these seeds is essentially associated with a low level of industrialization. In this context, extrusion cooking is a potential alternative for preparing extrudates of pinhão as a food product, which can be easily digested and is ready for human consumption. Brazilian pine seeds flour was processed in a single‐screw extruder following a central composite rotatable design. Three factors (independent parameters) were considered: moisture content (14 to 22 g/100 g), screw speed (100 to 250 rpm), and temperature in the 3rd heating zone (120 to 200 °C). The structural characteristics, in vitro digestibility and sensory acceptance were also evaluated. The resistant starch contents is almost reduced to zero after extrusion cooking while the slowly digestible starch content is increased. An increase in moisture positively affected the hardness and the luminosity (L^*), although it negatively affected the volumetric expansion index, crispness, and color parameters (a^*, b^*, and ΔE). The experimental conditions of this study allowed the production of expanded extrudates from Brazilian pine seeds with good expansion, texture properties, and acceptance qualities. Thus, extrusion cooking was found to be a potential method for the industrialization of Brazilian pine seeds as a food product.