Texture measurement approaches in fresh and processed foods — A review

Scanning electron microscopy combined with image processing technique: Analysis of microstructure, texture and tenderness in Semitendinous and Gluteus Medius bovine muscles

In this study the effect of freeze drying on the microstructure, texture, and tenderness of Semitendinous and Gluteus Medius bovine muscles were analyzed applying Scanning Electron Microscopy combined with image analysis. Samples were analyzed by Scanning Electron Microscopy at different magnifications (250, 500, and 1,000×). Texture parameters were analyzed by Texture analyzer and by image analysis. Tenderness by Warner-Bratzler shear force. Significant differences (p < 0.05) were obtained for image and instrumental texture features. A linear trend with a linear correlation was applied for instrumental and image features. Image texture features calculated from Gray Level Co-occurrence Matrix (homogeneity, contrast, entropy, correlation and energy) at 1,000× in both muscles had high correlations with instrumental features (chewiness, hardness, cohesiveness, and springiness). Tenderness showed a positive correlation in both muscles with image features (energy and homogeneity). Combing Scanning Electron Microscopy with image analysis can be a useful tool to analyze quality parameters in meat.Summary SCANNING 38:727-734, 2016. © 2016 Wiley Periodicals, Inc.

Characterization and stability studies of bioactive compounds and food matrices as evidence in support of health claims

The characterization and stability evaluation of food and food constituents (chemical active ingredient/microorganism) for which nutrition or health claims want to be requested are essential for the success of an application to EFSA. This work reviews the requirements that must be fulfilled for a full characterization of the active substance, comprising origin, elaboration, or extraction method, and chemical/microbiological composition, using validated analytical methods. The review focuses not only on establishing the specifications of the final active ingredient or food but also on ensuring homogeneity between batches. In addition, the article discusses the methodologies and conditions of the stability studies that need to be performed on food and food constituents to verify that the relevant compounds--chemical and microbiological active ingredients--will get to the consumer in the intended state and concentration to accomplish the claimed health effect over shelf life.

The influence of oral processing, food perception and social aspects on food consumption: a review

Eating is an essential activity to get energy and necessary nutrients for living. While chewing, the food is broken down by the teeth and dissolved by saliva. Taste, flavour and texture are perceived during chewing and will contribute to the appreciation of the food. The senses of taste and smell play an important role in selecting nutritive food instead of toxic substances. Also visual information of a food product is essential in the choice and the acceptance of food products, whereas auditory information obtained during the chewing of crispy products will provide information on whether a product is fresh or stale. Food perception does not just depend on one individual sense, but appears to be the result from multisensory integration of unimodal signals. Large differences in oral physiology parameters exist among individuals, which may lead to differences in food perception. Knowledge of the interplay between mastication and sensory experience for groups of individuals is important for the food industry to control quality and acceptability of their products. Environment factors during eating, like TV watching or electronic media use, may also play a role in food perception and the amount of food ingested. Distraction during eating a meal may lead to disregard about satiety and fullness feelings and thus to an increased risk of obesity. Genetic and social/cultural aspects seem to play an important role in taste sensitivity and food preference. Males generally show larger bite size, larger chewing power and a faster chewing rhythm than females. The size of swallowed particles seems to be larger for obese individuals, although there is no evidence until now of an 'obese chewing style'. Elderly people tend to have fewer teeth and consequently a less good masticatory performance, which may lead to lower intakes of raw food and dietary fibre. The influence of impaired mastication on food selection is still controversial, but it is likely that it may at least cause adaptation in food choice. Systemic conditions, such as high blood pressure, diabetes and cancer, with or without medicine use, tend to be associated with taste and chewing alterations. However, definite conclusions seem hard to reach, as research protocols vary largely.

Ethanol determination in frozen fruit pulps: an application of quantitative nuclear magnetic resonance

This study reports the chemical composition of five types of industrial frozen fruit pulps (acerola, cashew, grape, passion fruit and pineapple fruit pulps) and compares them with homemade pulps at two different stages of ripening. The fruit pulps were characterized by analyzing their metabolic profiles and determining their ethanol content using quantitative Nuclear Magnetic Resonance (qNMR). In addition, principal component analysis (PCA) was applied to extract more information from the NMR data. We detected ethanol in all industrial and homemade pulps; and acetic acid in cashew, grape and passion fruit industrial and homemade pulps. The ethanol content in some industrial pulps is above the level recommended by regulatory agencies and is near the levels of some post-ripened homemade pulps. This study demonstrates that qNMR can be used to rapidly detect ethanol content in frozen fruit pulps and food derivatives. Copyright © 2015 John Wiley & Sons, Ltd.

On-field monitoring of fruit ripening evolution and quality parameters in olive mutants using a portable NIR-AOTF device

This study optimizes the application of portable Near Infrared-Acousto Optically Tunable Filter (NIR) device to meet the increasing demand for cost-effective, non-invasive and easy-to-use methods for measuring physical and chemical properties during olive fruit development. Fruits from different phenotypically cultivars were sampled for firmness, total and specific phenols detection by HPLC, total anthocyanins, chlorophyll and carotenoids detection by spectrophotometry. On the same fruits, a portable NIR device in diffuse reflectance mode was employed for spectral detections. Predictive models for firmness, chlorophyll, anthocyanins, carotenoids and rutin were developed by Partial Least Square analysis. Oleuropein, verbascoside, 3,4-DHPEA-EDA, and total phenols were used to develop a validation model. Internal cross-validation was applied for calibration and predictive models. The standard errors for calibration, cross-validation, prediction, and RPD ratios (SD/SECV) were calculated as references for the model effectiveness. The determination of the optimal harvesting time facilitates the production of high quality extra virgin olive oil and table olives.

Prospects of breeding high-quality rice using post-genomic tools

The holistic understanding derived from integrating grain quality and sensory research outcomes in breeding high-quality rice in the light of post-genomics resources has been synthesized. Acceptance of new rice genotypes by producers and consumers hinges not only on their potential for higher yield but recent emphasis has also been on premium-value genotypes that have the ability to satisfy consumer preferences for grain quality. This review article provides insights into how to link grain quality attributes and sensory perception to support breeding superior rice varieties. Recent advances in quality profiling and omics technologies have provided efficient approaches to identify the key genes and biochemical markers involved in rice quality traits. Emphasis has been given to the upcoming area of holistic understanding of grain quality and attributes derived from sensory evaluation to leverage integrative gene discovery strategies that enable breeding programs to efficiently tap the huge genetic diversity in rice for novel genes that enhance rice food quality.

Comparison of selected sensory properties of wholemeal breads

The aim of this study was to compare textural (firmness) and sensory properties (surface colour, crumb colour, crumb texture, appearance, appearance and colour preferences) between whole breads made from conventional wheat (Triticum aestivum, L.) and whole breads made from unconventional wheat (Triticum aestivum, L., winter variety Skorpion, grains with blue aleuron). Wholemeal breads (control samples with marks C1, C2 and C3) were prepared of 100, 90 and 80 % amount of conventional wholemeal wheat flour to 0, 10 and 20% amount of smooth white flour made from conventional wheat using baker's experiment. Wholemeal breads (experimental samples with marks S1, S2 and S3) were prepared of unconventional wholemeal wheat flour to smooth white wheat flour in same ratio as control samples of breads. Our results showed, that negative evaluation of some sensory attributes of breads made from unconventional wheat correlated with increasing addition of wholemeal flour of this wheat. It was found that breads made from conventional wheat (100, 90 and 80% amount of conventional wholemeal flour) were more acceptable in surface colour, colour and appearance preferences than these sensory attributes of breads made from unconventional wheat (same amount of wholemeal flour). Appearance and crumb colour of breads made from conventional wheat (100 and 90% amount of wholemeal flour) were evaluated better than these attributes of breads made from blue coloured wheat (same amount of wholemeal flour). Appearance and crumb colour of both groups of whole wheat breads (80:20) was similarly evaluated. Crumb texture of breads made from conventional wheat (90% and 80% amount of wholemeal flour) was worse than crumb texture of breads produced of same ratio of flour, but made from unconventional wheat. Breads with addition of 80% of wholemeal flour milled of blue coloured wheat were most acceptable in all of sensory attributes for evaluators. Significant difference (p <0.05) of crumb fimness of breads were demonstrated between samples of breads (80:20) made from conventional or unconventional wheat. Crumbs of breads (100:0 and 80:20) made from blue coloured wheat had higher firmness than crumbs of breads (100:0 and 80:20) made from conventional wheat. But crumbs of breads (90:10) made from conventional wheat were firmer than crumbs of breads (90:10) made from unconventional wheat. Breads produced of blue coloured wheat were also more friable than breads made from conventional wheat. Although evaluation of wholemeal breads made from unconventional wheat had not better scores than evaluation of wholemeal breads made from conventioval wheat, but evalution of breads produced of unconventional wheat wholemeal flour were not below average and its market position could be very high in the future, due to the content of health benefit substances, which will be the subject of further research.

Design and testing of small scale fish meat bone separator useful for fish processing

The present study relates to the food processing machinery and, more specifically machine for producing boneless comminuted meat from raw fish fillet. This machine is of belt and drum type meat bone separator designed for small scale fish processing in a continuous mode. The basic principal involved in this machine is compression force. The electric geared motor consists of 1HP and the conveyor belt has a linear velocity of 19 to 22 m min(-1), which was sufficient to debone the fish effectively. During the meat bone separation trials an efficiency up to 75 % on dressed fish weight basis was observed and with a capacity to separate 70 kg h(-1) of meat from fish at the machine speed of 25 rpm. During the trials, it was demonstrated that there was no significant change in the proximate composition of comminuted fish meat when compared to unprocessed fish meat. This design has a greater emphasis on hygiene, provision for cleaning-in-place (CIP) and gives cost effective need and reliability for small scale industries to produce fish meat in turn used for their value added products.

Effect of High Hydrostatic Pressure Combined with Moderate Heat to Inactivate Pressure-Resistant Bacteria in Water-Boiled Salted Duck

The objective of this work was to study the effect of high hydrostatic pressure combined with moderate heat to inactivate pressure-resistant bacteria in water-boiled salted duck meat (WBSDM), and to establish suitable procedures to improve the quality of WBSDM. The conditions (300 MPa/60 °C, 400 MPa/60 °C, and 500 MPa/50 °C) effectively inactivated the pressure-resistant bacteria (Bacillus cereus and Staphylococcus warneri) in WBSDM. Although more pressure-resistant than S. warneri, the above treatment conditions inactivated B. cereus more than 10(7) CFU/mL in buffer, and more than 10(6) CFU/g in WBSDM, and did not cause any changes in color, texture, or moisture content of products. The interaction between pressure and temperature is a more significant factor than only pressure in inactivating both B. cereus and S. warneri, the treatment of WBSDM at 400 MPa/ 60 °C/ 10 min is the most practical condition for postprocess of WBSDM after cooking.

Characterization and classification of Japanese consumer perceptions for beef tenderness using descriptive texture characteristics assessed by a trained sensory panel

Meat tenderness is an important characteristic in terms of consumer preference and satisfaction. However, each consumer may have his/her own criteria to judge meat tenderness, because consumers are neither selected nor trained like an expert sensory panel. This study aimed to characterize consumer tenderness using descriptive texture profiles such as chewiness and hardness assessed by a trained panel. Longissimus muscles cooked at four different end-point temperatures were subjected to a trained sensory panel (n=18) and consumer (n=107) tenderness tests. Multiple regression analysis showed that consumer tenderness was characterized as 'low-chewiness and low hardness texture.' Subsequently, consumers were divided into two groups by cluster analysis according to tenderness perceptions in each participant, and the two groups were characterized as 'tenderness is mainly low-chewiness' and 'tenderness is mainly low-hardness' for tenderness perception, respectively. These results demonstrate objective characteristics and variability of consumer meat tenderness, and provide new information regarding the evaluation and management of meat tenderness for meat manufacturers.

Tissue microstructure, physicochemical properties, and bioactive compound locations in different sweet pepper types

This article focuses on the location and content of some bioactive compounds in three different California sweet pepper types (red, green and yellow). The location was studied using different microscopic techniques, such as scanning electron microscopy at low temperatures (cryo-SEM) and light microscopy. Several physicochemical properties of the samples (carotenoid content, total soluble phenol content, antioxidant activity, dietary fibre content, total soluble solids content, pH and textural properties) were also examined. The degree of compaction and structuring of the cell wall was found to be indirectly related to solute transport at the cellular level and directly related to total dietary fibre content. The three types of pepper displayed formation and accumulation of phenolic aggregates and an active circulation of solutes. Yellow pepper tissue had the most labile cell walls and the highest transport of solutes. Red peppers could be suitable for obtaining extracts rich in carotenoid compounds, yellow peppers for obtaining phenolic compounds with a high antioxidant activity and green peppers for extracts with high dietary fibre content.