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。     

ANALYSIS OF FOOD CRUSHING SOUNDS DURING MASTICATION: TOTAL SOUND LEVEL STUDIES 1

The total sound level of airborne noise was measured continuously during consecutive chews of fresh and stale samples of potato chips and tortilla chips. Sensory estimations of crispness were also made. Samples were evaluated using both an open mouth and a closed mouth procedure. Analysis showed that the total sound level decreased as chewing progressed. Significant differences were observed between open mouth and closed mouth chewing, with the former displaying higher sound levels. However, there were no statistical differences in the sound levels between fresh and stale samples. Sensory assessments ofcrispness showed decreasing crispness as chewing progressed. Statistical differences were observed in the sensory evaluations between fresh and stale samples. Openmouth sensory evaluations were significantly different from closed-mouth evaluations for potato chips but not for tortilla chips. Good correlations were observed between the acoustic measurements and the sensory estimations, in agreement with the work of other investigators.     

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.     

INSTRUMENTAL MEASURES OF BITE FORCES ASSOCIATED WITH CRISP PRODUCTS

The usefulness of a bite force apparatus for measuring bite forces generated while biting extruded crisp snacks was assessed. Snacks were produced using a twin‐screw extruder, and their textural properties were modified by equilibrating to water activities ranging from 0.11 to 0.44. Maximum force to bite, stress, duration and area under the bite force curve were analyzed and compared to perceived sensory crispness, hardness, brittleness and sound duration evaluated by eight individuals. Maximum bite force and stress were significantly related to hardness, brittleness and crispness showing for the first time, and the relationship between sensory crispness of extruded crisp products and hardness was measured intraorally.     

Mechanical and acoustic evaluation of potato chip crispness using a versatile texture analyzer

The crispness of different potato chip samples was evaluated by uniaxial compression using a widely employed instrument. Acoustic and mechanical events were measured simultaneously during deformation and fracture of the samples at a constant speed. We particularly focused on the mechanical and acoustic characteristics in the vicinity of the major fracture point to confirm the hypothesis that the crispness of potato chips is perceived when they are totally fractured. The results indicated a significant correlation between the magnitudes of the force drop at the fracture point and associated sound pressure. The magnitude of the force drops at the major fracture point differed significantly among the samples, however, the results did not perfectly reflected the perceived crispness of the potato chip samples.     

Sensory, Acoustical, and Force-Deformation Measurements of Potato Chip Crispness

The auditory (sound only) and oral (normal biting and chewing) crispness of five different potato chip products, each adjusted to two moisture contents, were measured. Instrumental acoustical and force-deformation measurements were made on these same samples and compared with the sensory crispness measurements. Oral crispness judgments appeared to be made on the basis of both auditory and oral tactile sensations, since auditory crispness was not highly correlated to oral crispness. A combination of acoustical and force-deformation measurements provided an excellent measure of oral chip crispness.     

ACOUSTIC TESTING OF SNACK FOOD CRISPNESS USING NEURAL NETWORKS

The crispness of selected snack foods, Pringles potato chips, Paprika extruded snack and Munchy crackers, was evaluated by crushing the snack samples with a pair of pincers, and analyzing the frequency domain spectra of acoustic patterns by the neural networks (NNs). The inputs for training the NNs comprised 102 amplitudes of sound signals in 0–7 kHz frequency range at the intervals of about 69 Hz with moisture content or crispness grades as outputs. Both backpropagation (BPNN) and probabilistic (PNN) models showed good performance in classifying the snack foods into four grades of sensory crispness. The prediction accuracy of PNN models ranged approximately from 96 to 98% and was higher than the accuracy of BPNN models by about 10 to 25%. Results showed that frequency domain spectra of acoustic signals could be successfully analyzed by the NNs for predicting the crispness of snack food products.     

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。     

Instrumental and sensory evaluation of crispness: I—In friable foods

Using the Constant Loading Rate Texture Testing instrument it was possible to extract from the deformation/time and force/time curves together with the sound emitted from the samples during the test, those variables included in both the definition of crispness and the assumption that in the case of friable foods crispness may be regarded as ‘compressive brittleness’.Significant correlations (P<0·01) were obtained between sensory crispness and the instrumental variables: equivalent sound level L_eq (r = 0·701), ratio of work done during fracture to total work W_F/W_T (r = 0·878) and fracture or collapse rate (r = 0·570).A poor correlation between sensory crispness and both sensory hardness (r = 0·398) and instrumental fracture force (r = 0·018) indicates that a hard friable food material is not necessarily a crisp one, whereas the highly significant correlation between sensory crispness and both sensory sound intensity (r = 0·908) and instrumental L_eq (r = 0·701) indicates the importance of sound in the sensory and instrumental evaluations.The results of regression analysis showed a number of almost equally well fitting equations with the ratio W_F/W_T and L_eq as the dominant variables in predicting sensory crispness in friable foods.     

Methodological developments in crispness assessment: Effects of cooking method on the crispness of crusted foods

A new method was developed to assess the texture of crispy-crusted foods with a soft, high-moisture core. This method, applied to commercial pre-cooked chicken nuggets, combines characteristics derived from the force/displacement curves of the whole sample with characteristics of the simultaneously emitted sound. The use of a not-sharp blade probe to perform the test proved to be an effective technique for characterizing the texture of chicken nuggets after different final cooking processes. The force curves of the samples differed with the cooking process. Deep-fried samples and those cooked in a conventional oven presented jagged force curves and acoustic signals with many peaks, both characteristics of crispy products. The curve profiles of microwaved samples were drastically different and typical of tough, gummy products. The use of a susceptor package in microwave heating improved the crispness of the samples. The number of sound peaks was the acoustic parameter that best discriminated between the samples. It was found that although the moisture and fat contents of the core and crust are closely related to the texture characteristics, samples with similar water contents can have very dissimilar crispness characteristics. The fat content of the core did not change significantly with the final cooking process in any of the samples.     

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.     

Characterization of crispness of French fries by fracture and acoustic measurements,effect of pre-frying and final frying times

The influence of pre-frying and final frying time on the crispness of French fries was evaluated by simultaneous analysis of the fracture and acoustic properties during instrumental simulation of human chewing. The analysis of the frequency distribution of the force and sound events corresponding to the crust of the French fry reflected an effect of both pre-frying and final frying time on instrumental crispness. Up to 60 s pre-frying, an increase in the number and magnitude of force and sound events was found, which reflect an increase in crispness. The increase in final frying time increased crispness, but it cannot counterbalance a lack of pre-frying. The moisture content of the whole French fries cannot explained the effect of pre-frying on crispness. Conversely, the effect of pre-frying can be explained when considering only the moisture content of the crust. Pre-frying may allow an easier loss of water from the crust during final frying, which will enhance its crispness.     

猕猴桃品种对猕猴桃脆片品质影响的评价

目的:以6个品种的猕猴桃为原料,筛选出最适合加工成脆片的品种。方法:采用真空冷冻干燥的方法制备猕猴桃脆片,测定猕猴桃脆片的得率、脆片中水溶性果胶含量、酸溶性果胶含量、可溶性糖含量、总酸含量、糖酸比、抗坏血酸含量及脆片的硬度和脆度等9个指标,并对猕猴桃脆片进行感官评价。结果:不同品种猕猴桃脆片的得率、营养物质含量和感官指标不同。其中金艳猕猴桃脆片的得率、水溶性果胶含量、可溶性糖含量和硬度较高,总酸含量和脆度较低;金梅猕猴桃脆片的得率、水溶性果胶含量、可溶性糖含量和抗坏血酸含量较高,总酸含量、硬度和脆度较低;金圆猕猴桃脆片的水溶性果胶、酸溶性果胶、结合果胶、可溶性糖、总酸和抗坏血酸含量较高,脆片的硬度和脆度较低;金桃猕猴桃脆片的得率、糖酸比、抗坏血酸等含量及脆片的硬度和脆度较高,脆片的水溶性果胶和总酸含量较低;翠玉猕猴桃脆片的得率、糖酸比和脆度较高,脆片的酸溶性果胶含量、结合态果胶含量、可溶性糖含量、总酸含量和脆片的硬度较低;东红猕猴桃脆片的得率、酸溶性果胶含量、结合态果胶含量、可溶性糖含量、糖酸比和脆片的硬度较高,脆片中水溶性果胶含量、总酸含量和脆片的脆度较低。结论:品种对猕猴桃脆片的得...     

Understanding and predicting sensory crispness of deep‐fried battered and breaded coatings

Crusted crispness refers to coatings with a dry and brittle surface contrasting a high‐moisture core; it is desirable for the enjoyment and quality of deep‐fried goods. This study aims to investigate instrumental measurements and sensory measurements of crispness. Deep‐fried breadcrumb coatings of eight sizes were investigated: 4.0 mm, 2.8 mm, 2.0 mm, 1.4 mm, 1.0 mm, 710 μm, 500 μm, and 355 μm. Sensory profiling was carried out to develop a tailored lexicon for deep‐fried battered and breaded shrimp. Principal component analysis highlights that large breadcrumb sizes correlate with crispness, hardness, particle size, surface color, color uniformity, surface irregularity, total porosity, maximum force, area, drop in force, number of sound peaks, and sound pressure level. Agglomerative hierarchical clustering was used to confirm clustering of samples according to breadcrumb size. Multiple factor analysis confirmed overall correlation between sensory measurements and instrumental measurements (RV = 0.810). Partial least squares regression was used to develop a predictive model for crispness from instrumental measurements (R² = .854). The use of texture analysis and Acoustics provide information of the structures strength and deformation behavior, while X‐ray microCT provides a high resolution and noninvasive method that acquires information on the internal morphology. These instrumental methods collectively demonstrate the relationship between microstructure to sensory. This study investigates how a change in the microstructure of deep‐fried battered and breaded coatings affect crispness perception. These changes were investigated analytically and by using a sensory panel, this is important from a manufacturing perspective in order to understand what the major contributors are to a crisp texture. The key highlights of this study include both instrumental measurements and sensory measurements can be used to measure crispness as both types of testing are correlated. Changes in the size of breadcrumbs affect both instrumental measurements and sensory measurements. A predictive model can be re‐simulated to allow prediction of crispness in deep‐fried battered and breaded coatings.     

Predicting the sensory crispness of coated turkey breast by its acoustic signature

Crispness of coated turkey breast after frying, and reheating by microwave or oven, was evaluated by sensory, mechanical tests and a newly developed acoustic signature-classifying model (ASCM). The acoustic signatures were recorded during compression-tests and analyzed by the ASCM. Support vector machines (SVM) and Fuzzy KNN classifiers were used to performed classification of the acoustic signals to frying, and heating by microwave or oven. The sensory crispness scores and the initial slope of the force deformation curve were predicted using frequency domain spectra of the acoustic signals by neural networks (NN). The results showed that a linear classifier (LC) provides satisfying predictions of the sensory crispness grades and the initial slope of the force deformation curve for fried and microwave heated samples.     

Sensory and instrumental measurement of food crispness: II — In a high moisture food

Preliminary attempts to compress cylinders of apple tissue under constant loading rate to obtain catastrophic breakdown of the samples were unsuccessful. Puncture and ‘biting’ tests, where the shear component was dominant, yielded some useful results. Highly significant correlations (p < 0·001) were obtained between sensory crispness and sensory hardness and between sensory crispness and most of the physical measurements obtained when using these two tests. The measurements chosen for the regression analysis (equivalent sound level, fracture rate and work done during fracture) were those thought to be of significance in the sensory measurement and included in the definition of crispness.The results of the regression analysis show that both the ‘biting’ and puncture tests produced a number of almost equally-well-fitting equations with the equivalent sound level and the work done during fracture as the dominant variables in predicting sensory crispness in a high moisture food. The regression equations of the ‘biting’ test always tend to give a better prediction of crispness (higher values of R²) than the respective puncture test equations.The values of the maximum sound levels in octave bandwidths over the audible range for the fresh and stored apples show the same broad spectrum, with the stored samples producing, in general, less sound at all frequencies, significantly so for frequencies greater than 3 kHz.     

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.     

马铃薯脆片微波干燥工艺研究

研究了微波不同处理对马铃薯脆片的影响。微波功率高,则脆片的脆度好,合适的微波处理时间可以得到较好脆度的马铃薯脆片。冷冻处理可以得到变形小,表面颜色均匀的良好脆片,初始含水量15%左右的薯片进行微波加工具有较大的膨化率。