Tomato Peel Research Articles

Preparation of biomass fiber/polylactic acid foam using an oven-type free foaming method for energy savings and performance enhancement

Given the inherent challenges of low melt strength and slow crystallization rate associated with polylactic acid (PLA), this study introduces a sustainable and efficacious approach to enhance PLA crystallization utilizing biomass tomato peel pomace powder (TP) as a heterogeneous nucleating agent. ZnO-modified azodicarbonamide (ADC) was used as the chemical blowing agent. The blends were prepared with the aid of a torque rheometer, and TP/PLA composite foams were successfully prepared by the oven-type free foaming method. The empirical results demonstrate that the TP/PLA composite foam exhibits reduced processing requirements and superior comprehensive properties compared to pure PLA foam. Specifically, the composite containing 5 wt% TP achieved optimal foaming performance with 3 phr blowing agents and a foaming duration of 10 min. Furthermore, the annealing treatment markedly enhanced the compression modulus and strength of the foams. Under annealing conditions of 110 °C for 30 min, the compressive strength of the foam increased by 483.5 % relative to the untreated sample. The development of this composite foam signifies a novel direction for energy-efficient performance enhancement and holds significant potential for applications in building insulation and packaging industries.

Hierarchical Porous Biowaste‐Based Dual Humidity/Pressure Sensor for Robotic Tactile Sensing, Sustainable Health, and Environmental Monitoring

A crucial tradeoff between material efficacy and environmental impact is often encountered in the development of high‐performance sensors. The use of rare‐earth elements or intricate fabrication techniques is sometimes needed for conventional sensing materials, posing concerns regarding sustainability. Exploring the potential of tomato peel (TP) as a dual‐purpose sensing dielectric layer for pressure and humidity monitoring is a paradigm shift, capitalizing on its porous structure and hygroscopic nature. TP‐based humidity sensor (TP‐HS) exhibits impressive results, with a wide humidity sensing range (5%–95%), fast response/recovery time (6.5/9 s), a high sensitivity (12 500 pF %RH−1), and a high stability (30 days). Additionally, TP‐based pressure sensor (TP‐PS) also shows excellent performance in accurately sensing pressure changes in a wide range (0–196 kPa). TP‐HS can easily distinguish between breathing rates (normal, fast, and slow) and moisture content present in different moisturizers (aloe vera and sanitizer) along with its successful use for proximity sensing. Alternatively, TP‐PS demonstrates weight measurement (490 and 980 N), grip recognition (measuring the pressure exerted by each finger), and gesture detection (by monitoring multiple bending angles 0°, 30°, 50°, and 80°). A wearable, biocompatible dual sensor based on a promising sustainable material for environmental, robotic, and health monitoring applications is successfully demonstrated.

Dehydration of tomato peels and seeds as affected by the temperature

SummaryAn empirical model was developed for dehydrating tomato's peels and seeds (TPS) at three different temperatures (i.e. 50 °C, 60 °C and 70 °C). The model assumes that there is an initial constant drying rate period (first stage) followed by a decreasing drying rate period (second stage). To assess the goodness of fitting procedure, the mean relative deviation modulus was calculated. Results indicate that the model can adequately describe the dehydration data. The robustness of the model was further tested by evaluating the dependence of model parameters on the temperature, using an Arrhenius‐type equation. Recorded findings show that model parameters changed with the temperature, thus confirming that the proposed model can be advantageously used to describe the dehydration kinetic of TPS. The influence of TPS dehydration on temperature was also assessed by calculating the dehydration rate as function of TPS water content. Results demonstrate that the dehydration rate increases as the testing temperature increases too. In both drying stages, the difference between the dehydration rate at 50 °C and the one at the other two temperatures is more marked.

A Novel Workflow for In Silico Prediction of Bioactive Peptides: An Exploration of Solanum lycopersicum By-Products.

Resource-intensive processes currently hamper the discovery of bioactive peptides (BAPs) from food by-products. To streamline this process, in silico approaches present a promising alternative. This study presents a novel computational workflow to predict peptide release, bioactivity, and bioavailability, significantly accelerating BAP discovery. The computational flowchart has been designed to identify and optimize critical enzymes involved in protein hydrolysis but also incorporates multi-enzyme screening. This feature is crucial for identifying the most effective enzyme combinations that yield the highest abundance of BAPs across different bioactive classes (anticancer, antidiabetic, antihypertensive, anti-inflammatory, and antimicrobial). Our process can be modulated to extract diverse BAP types efficiently from the same source. Here, we show the potentiality of our method for the identification of diverse types of BAPs from by-products generated from Solanum lycopersicum, the widely cultivated tomato plant, whose industrial processing generates a huge amount of waste, especially tomato peel. In particular, we optimized tomato by-products for bioactive peptide production by selecting cultivars like Line27859 and integrating large-scale gene expression. By integrating these advanced methods, we can maximize the value of by-products, contributing to a more circular and eco-friendly production process while advancing the development of valuable bioactive compounds.

From Waste to Consumption: Tomato Peel Flour in Hamburger Patty Production.

Tomato is a widely cultivated crop and its processing produces large quantities of wastes, such as pulp, seed, and peel. In recent years, the valorization of these wastes in the production of high-value-added food products has gained popularity in achieving environmental sustainability and zero waste. From this viewpoint, dried tomato peel (DTP-1%, 2%, 3%, 4%) flour was included in hamburger formulations. In patty samples, ash, carbohydrate, and dietary fiber amounts were increased due to the high fiber content of DTP flour, while moisture and fat percentages decreased with increasing amounts of DTP flour (p < 0.05). The inclusion of DTP flour retarded lipid oxidation during cooking (p < 0.05). The significantly highest cooking yield was calculated in samples including 4% DTP flour. In parallel, water-holding capacity, moisture, and fat retention values increased with increasing levels of DTP flour (p < 0.05). The enrichment of patties with DTP flour resulted in hard texture, less gumminess, and a darker, more reddish and yellowish color (p < 0.05). Hamburger samples containing 1% or 2% DTP flour were graded with closer scores in the sensory panel as compared to the control (0% DTP). Overall, our findings demonstrated that DTP flour up to 2% could be used to improve the nutritional and technological properties of patty samples.

Characterization of the Polyphenolic Profile in Tomato (Lycopersicon esculentum P. Mill) Peel and Seeds by LC-HRMS/MS.

Peel and seeds are the main byproducts from tomato (Lycopersicon esculentum P. Mill) processing with high concentrations of polyphenols that have been underexploited. Herein, polyphenolic profiles in tomato peel and seeds were elucidated by untargeted liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) with an LTQ Orbitrap analyzer. Samples from two Spanish regions─"Murcia" and "Almería"─were analyzed to obtain complementary results. 57 compounds were found, mainly phenolic acids and flavonoids, of which eight were identified for the first time in tomato. Polyphenols were more abundant in byproducts from "Murcia" samples than in those from"Almería" samples, where the abundance of compounds like coutaric, caffeic, neochlorogenic, dicaffeoylquinic and ferulic acids, vanillic acid hexoside, catechin, naringenin, prunin, apigenin-O-hexoside, rutin, and rutin-O-pentoside was even much higher in byproducts than that in whole fruits. These results reveal the wide range of polyphenols found in tomato byproducts, with potential applications in pharmaceutical research, food preservation, and cosmetic development, among others.

Potential Use of Tomato Peel, a Rich Source of Lycopene, for Cancer Treatment.

Tomatoes are well known for their impressive nutritional value among vegetables. However, the industrial processing of tomatoes generates a significant amount of waste. Specifically, 10% to 18% of the raw materials used in tomato processing become waste. This waste can seriously affect ecosystems, such as freshwater bodies, wetlands, rivers, and other natural environments, if not properly managed. Interestingly, tomato waste, specifically the skin, contains lycopene, a potent antioxidant and antimutagenic that offers a range of health benefits. This makes it a valuable ingredient in industries such as food and cosmetics. In addition, researchers are exploring the potential of lycopene in the treatment of various types of cancer. This systematic review, guided by the PRISMA 2020 methodology, examined studies exploring the possibility of tomato peel as a source of lycopene and carotenoids for cancer treatment. The findings suggest that tomato peel extracts exhibit promising anticancer properties, underscoring the need for further investigation of possible therapeutic applications. The compiled literature reveals significant potential for using tomato peel to create new cancer treatments, which could potentially revolutionize the field of oncology. This underscores the importance of continued research and exploration, emphasizing the urgency and importance of the scientific community's contribution to this promising area of study.

Impact of Simulated Human Gastrointestinal Digestion on the Functional Properties of Dietary Fibres Obtained from Broccoli Leaves, Grape Stems, Pomegranate and Tomato Peels.

This study aimed to analyse the impact of a simulated human digestion process on the composition and functional properties of dietary fibres derived from pomegranate-peel, tomato-peel, broccoli-stem and grape-stem by-products. For this purpose, a computer-controlled simulated digestion system consisting of three bioreactors (simulating the stomach, small intestine and colon) was utilised. Non-extractable phenols associated with dietary fibre and their influence on antioxidant capacity and antiproliferative activity were investigated throughout the simulated digestive phases. Additionally, the modifications in oligosaccharide composition, the microbiological population and short-chain fatty acids produced within the digestion media were examined. The type and composition of each dietary fibre significantly influenced its functional properties and behaviour during intestinal transit. Notably, the dietary fibre from the pomegranate peel retained its high phenol content throughout colon digestion, potentially enhancing intestinal health due to its strong antioxidant activity. Similarly, the dietary fibre from broccoli stems and pomegranate peel demonstrated anti-proliferative effects in both the small and the large intestines, prompting significant modifications in colonic microbiology. Moreover, these fibre types promoted the growth of bifidobacteria over lactic acid bacteria. Thus, these results suggest that the dietary fibre from pomegranate peel seems to be a promising functional food ingredient for improving human health.

Flame-catalytic infrared dry system for tomato continuous peeling

To eliminate the need for alkali and excess water while accelerating the industrial application of dry tomato peeling, a highly efficient industrial flame-catalytic infrared continuous peeling apparatus was designed. The synthesis of the catalytic layer (Pt/Al2O3) within the device was optimized to improve cost-effectiveness and enable modular installation, making it suitable for industrial applications. This study determined the optimal production parameters for industrial flame-catalytic infrared peeling (F-CIP) through experiments. Current findings demonstrated that, under optimal F-CIP conditions, characterized by a flame heating time of 5.8 s, an infrared heating temperature of 456 °C, an infrared heating distance of 70.6 mm, and an infrared heating duration of 246 s, peeling efficiency reached 99.2±0.9 %, with a peel loss of 4.1±0.3 %. Comparative analysis with lye peeling (LP) and hot water peeling (HWP) showed that F-CIP reduced hardness and peel loss and better preserved nutritional and antioxidant compounds. The mechanism responsible for the loosening and cracking of the fruit skin in the F-CIP peeling process involved a reduction in adhesion between the skin and the pulp due to the alteration of the pectin structure, an expansion of cell structure due to internal vaporization, and an increase in the Young’s modulus of the tomato skin. The F-CIP method, with its proven peeling efficiency, energy-saving attributes, and environmentally friendly features, is expected to attract increased attention from equipment manufacturers and the tomato industry. This paper serves as a foundational guide and contributes to the application and parameter control of F-CIP in the tomato peeling.

Tomato Residue Management from a Biorefinery Perspective and towards a Circular Economy.

The tomato industry is a relevant socio-economic activity in the European Union, while it generates a large variety of residues. Tomatoes unfit for consumption, tomato peels, seeds, industrial pomace, and plants are examples of residues of this industry. Commonly, some of the residues can be left in the field, composted, used for animal feeding, or valorized through anaerobic digestion. However, more economic value can be attributed to these residues if a biorefinery approach is applied. Indeed, many value-added compounds can be obtained by the integration of different processes while closing the carbon and nutrient loops. The extraction of bioactive compounds followed by anaerobic digestion and composting seems to be a viable proposal for a biorefinery approach. Thus, this study aims to review the biorefinery strategies for valorizing tomato residues, highlighting the main processes proposed. The recovery of lycopene, β-carotene, and phenolic compounds has been widely studied at the lab scale, while energy recovery has already been applied at the industrial scale. Although techno-economic analysis is scarce for tomato residue valorization processes, positive net present values (NPV) and low payback times (PBT) have been reported in the literature. Thus, more work comparing multiple extraction technologies and biorefinery strategies coupled with economic and environmental assessment should be performed to select the most promising management route for tomato residues.

Increasing sustainability in the tomato processing industry: environmental impact analysis and future development scenarios

IntroductionThe agri-food sector has been identified as one of the most significant contributors to environmental degradation and emissions. Thus, in order to respond to the societal demand for cleaner and greener products, in recent years, the food industry has been striving to identify and apply more sustainable practices to minimize the negative impact on the environment. Within the agri-food sector, one of the industries requiring efforts to mitigate its environmental footprint is the tomato processing industry, which represents an important industry within the Italian industrial food processing sector. Efficient utilization of resources and adoption of innovative methods in the production lines of the tomato processing industry can be envisaged as strategic measures to increase sustainability. This study aims to discuss the results of the case study in which an Italian tomato processing company has been analyzed by applying the LCA methodology.MethodForeground data were obtained from the tomato processing facility located in southern Italy, and Ecoinvent database was the source of background data. The assessment was carried out by SimaPro software using ReCiPe 2016 (V1.03). The feasible conservation strategies in the production line have been evaluated through water-energy nexus simulation by SuperPro Designer® before the implementation, and different scenarios have been evaluated by SimaPro to decrease the environmental load.Results and conclusionThis study demonstrates that the production of 1 kg of peeled tomatoes and tomato puree leads to greenhouse gas emissions of 0.083 kg CO2 eq and 0.135 kg CO2 eq, respectively. A deeper analysis to evaluate the contribution of the different tomato processing stages indicated that the thermal units are the main ones responsible for adverse effects on the environment, and any improvement in their performance can be seen as an unmissable opportunity. The conservation strategies identified resulted in considerable water (23.4%), electricity (14.7%), and methane (28.7%) savings and, consequently, in 16 and 19% reduction of global warming potential in peeled tomato and tomato puree production lines, respectively. These findings provide new insights for tomato processing companies wishing to adopt more sustainable processing practices, reducing their environmental impact to a considerable extent and improving their economic performance.

Microwave-assisted extraction, encapsulation, and bioaccessibility of carotenoids from organic tomato industry by-product

Tomato (Solanum lycopersicum) is a widely consumed fruit in the world. Discarded biomass has a huge potential, as tomato peel is rich in carotenoid content. This study focuses on the recovery of carotenoids from tomato industry agro-wastes, specifically peel and seeds. Initially, the conventional method was employed to analyze the sample, determining a total carotenoid content of 3.19 ± 0.23 mg β-carotene eq/g dry matter. A carotenoid profiling of the sample revealed high concentration of 5-cis-lycopene (1340.1 ± 15.6 μg all-trans-β-carotene eq/g dry matter), 9-cis lycopene (1062.7 ± 12.8 μg all-trans-β-carotene eq/g dry matter) and all-trans-β-carotene (1246.4 ± 1.7 μg all-trans-β-carotene eq/g dry matter). Microwave-assisted extraction (MAE) was employed as a green extraction method to optimize biomass-solvent ratio (BSR), extraction time (ET), and microwave power (MP) for achieving maximum recovery of carotenoids. A surface response methodology based on a Box-Behnken design was used. The optimized extract (BSR 1:10 g:mL, ET 60 s, and MP 283.84 W) was microencapsulated using maltodextrin (MD) combined with either gum arabic (GA) or whey protein isolate (WP) as wall materials. Freeze-drying was utilized for capsule sealing. The properties of the encapsulates were characterized, including moisture content (0.99 ± 0.04% for MD:GA and 0.80 ± 0.07% for MD:WP), water activity (0.087 ± 0.01 for MD:GA and 0.084 ± 0.01 for MD:WP), dissolution rate (140.4 1 ± 6.41 s for MD:GA and 86.49 ± 1.68 s for MD:WP), tapped density (0.48 ± 0.01 g/mL for MD:GA and 0.44 ± 0.01 g/mL for MD:WP), drying yield (90.73 ± 3.34% for MD:GA and 89.73 ± 3.47% for MD:WP), and encapsulation efficiency (68.12 ± 1.42% for MD:GA and 74.55 ± 1.62% for MD:WP). Bioaccessibility studies for encapsulated extract revealed values of 27.68% ± 0.72 and 25.10% ± 0.04 for MD:GA and MD: WP, respectively. This research highlights the potential of tomato agro-wastes as a valuable source of bioactive compounds. The implementation of MAE and microencapsulation techniques demonstrates effective strategies for their recovery and preservation obtaining the optimal conditions for the MAE (BSR 1:10 g: mL, ET 60 s, and MP 283.84 W) and for the encapsulation (MD: WP mixture). These findings contribute to the valorization of tomato industry by-products and their potential application in functional food products.

Preparation of tomato peel pomace powder/polylactic acid foams under supercritical CO2 conditions: Improvements in cell structure and foaming behavior

Polylactic acid (PLA) is an eco-friendly material that can help address the problems of petroleum depletion and pollution. Blending renewable biomass materials with PLA to create composite foams with a tunable pore structure, superior performance, and low cost is a green technique for improving the pore structure and mechanical characteristics of single PLA foams. PLA/TP composites were created using melted tomato peel pomace powder (TP), which has a lamellar structure, as a reinforcing agent. Then, the relationship between the vesicle structure, morphology, and properties of the PLA/TP composite foams produced through supercritical CO2 intermittent foaming were investigated. The findings revealed that TP considerably enhanced the rheological characteristics and crystalline behavior of PLA. The PLA/TP composite foam had a better cell structure, compression characteristics, and wettability than pure PLA. The expansion ratio of the PLA/TP composite could reach 18.8, and its thermal conductivity decreased from 174.2 mW/m·K at 100 °C to 57.8 mW/m·K at 120 °C. Furthermore, annealing before foaming decreased the average composite foam blister size from 110.09 to 66.53 μm, and the annealing process also improved compression performance. This study contributes to solving environmental difficulties and creating PLA foams with controlled bubble structures, uniform bubble sizes, and outstanding overall performance.

Enhancing Cutin Extraction Efficiency from Industrially Derived Tomato Processing Residues by High-Pressure Homogenization.

This study primarily aimed to enhance the extraction of cutin from industrial tomato peel residues. Initially, the conventional extraction process was optimized using response surface methodology (RSM). Subsequently, high-pressure homogenization (HPH) was introduced to improve extraction efficiency and sustainability. The optimization process focused on determining the optimal conditions for conventional extraction via chemical hydrolysis, including temperature (100-130 °C), time (15-120 min), and NaOH concentration (1-3%). The optimized conditions, determined as 130 °C, 120 min, and 3% NaOH solution, yielded a maximum cutin extraction of 32.5%. Furthermore, the results indicated that applying HPH pre-treatment to tomato peels before alkaline hydrolysis significantly increased the cutin extraction yield, reaching 46.1%. This represents an approximately 42% increase compared to the conventional process. Importantly, HPH pre-treatment enabled cutin extraction under milder conditions using a 2% NaOH solution, reducing NaOH usage by 33%, while still achieving a substantial cutin yield of 45.6%. FT-IR analysis confirmed that cutin obtained via both conventional and HPH-assisted extraction exhibited similar chemical structures, indicating that the main chemical groups and structure of cutin remained unaltered by HPH treatment. Furthermore, cutin extracts from both conventional and HPH-assisted extraction demonstrated thermal stability up to approximately 200 °C, with less than 5% weight loss according to TGA analysis. These findings underscore the potential of HPH technology to significantly enhance cutin extraction yield from tomato peel residues while utilizing milder chemical hydrolysis conditions, thereby promoting a more sustainable and efficient cutin extraction process.

Crosslinked Polyesters as Fully Biobased Coatings with Cutin Monomer from Tomato Peel Wastes.

Cutin, one of the main structural components of tomato peels, is a waxy biopolymer rich in hydroxylated fatty acids. In this study, 10,16-dihydroxyhexadecanoic acid (10,16-diHHDA) was extracted and isolated from tomato peels and exploited to develop fully crosslinked polyesters as potential candidates for replacing fossil-based metal protective coatings. A preliminary screening was conducted to select the base formulation, and then a design of experiments (DoE) was used as a methodology to identify the optimal composition to develop a suitable coating material. Different formulations containing 10,16-diHHDA and other biorefinery monomers, including 2,5-furandicarboxylic acid, were considered. To this end, all polyesters were characterized through differential scanning calorimetry (DSC) and gel content measurements to determine their Tg value and crosslinking efficiency. Compositions exhibiting the best trade-off between Tg value, chemical resistance, and sufficiently high 10,16-diHHDA content between 39 and 48 wt.% were used to prepare model coatings that were characterized for assessing their wettability, scratch hardness, chemical resistance, and adhesion to metal substrates. These polyester coatings showed a Tg in the range of 45-55 °C, a hydrophobic behavior with a water contact angle of around 100°, a good solvent resistance (>100 MEK double rubs), and an adhesion strength to steel higher than 2 MPa. The results obtained confirmed the potential of cutin-based resins as coatings for metal protection, meeting the requirements for ensuring physicochemical properties of the final product, as well as for optimizing the valorization of such an abundant agri-food waste as tomato peels.

In and out Beauty and Sensitive Skin, a Psychophysiological Exploration: Myth or Reality?

Knowing that biomolecules, such as β-amyrin and α-amyrin, have some pharmacological effects, the aim of this study was directed towards exploring the protective effect of Tomato Peel and Seed Extract (TPSE) for its soothing function but also for its capacity to modulate the adrenal axis, which is involved in stress response. Ex vivo tests were carried out on skin explants to evaluate the effectiveness of TPSE formulated at 0.5% on Calcitonin Gene-Related Peptide (CGRP) and IL-10 release, Kappa Opioid Receptor (KOR), and Caspase 14 expression. An in vivo study combined a clinical evaluation of skin homogeneity and psychological parameters as well as an analysis of salivary cortisol and dehydroepiandrosterone concentrations. All measurements were carried out at the beginning and after 28 days of applying a TPSE face cream. TPSE regulated not only the release of CGRP, IL-10, and the expression of Caspase 14, reflecting anti-neurogenic and anti-inflammatory properties, but also modulated KORs. Twenty-eight days of TPSE application induced a significant decrease in intensity and extent erythrosis, a lower output of salivary cortisol, and a significant increase in pleasant emotions when compared to placebo. These results provide encouragement to continue exploring the impact of cosmetic ingredients on psychophysiological parameters to improve skin health and well-being.

Optimization of Mechanical, Optical, Barrier and Bioactive Properties of Edible Films from Tomato Puree, Tomato Peels and Moringa Leaf Extract

Optimization of Mechanical, Optical, Barrier and Bioactive Properties of Edible Films from Tomato Puree, Tomato Peels and Moringa Leaf Extract

Rheological and sensorial behavior of tomato product enriched with pea protein and olive powder

In this study, a new functional product using Mediterranean ingredients (tomato, tomato peel powder and olive powder) was formulated where two different concentrations of protein (1 and 2%) and peel (2 and 4%) were tested. Olive powder was kept at a constant concentration of 2%. Physico-chemical, Rheological, and Sensorial analysis were carried out on the formulated samples. Soluble protein content was found as the highest in the sample containing 4% peel and 2% protein and it was affected by the pH and tomato peel concentration. Rheological results reveal shear-thinning behavior, as defined by the Herschel-Bulkley model, with protein and peel concentrations having a major influence on yield stress and viscosity. A positive trend was noticed between apparent viscosity and peel concentration, meantime protein concentration affected apparent viscosity adversely. Contrary relation between consistency index (k) values and apparent viscosity illustrate the complex interaction between protein and peel, particularly at higher concentrations. Furthermore, Principal Component Analysis (PCA) was used to investigate the complicated sensory landscape of tomato products with different quantities of pea protein and tomato peel. While higher tomato peel and protein levels have no direct impact on rheological qualities, they do add to astringency and sourness, which influences overall acceptability. Remarkably, the sample with the greatest quantities of peel and protein exhibits a delicate balance, with a loss in perceived tomato taste intensity and overall acceptability offsetting an increase in astringency. In terms of overall acceptability, the most preferred beverage was selected as the sample formulated with 2% peel and 1% protein.

A comparative analysis of cutin monomers from cereal brans and fruit peels: Isolation and characterization

Plant cuticles contain mainly lipid polymers (cutin), protecting them against desiccation and environmental stresses. The monomeric composition of the cuticular polymer fractions of three cereal fibers: maize bran, wheat bran and sorghum bran, as well as hemicellulose/cellulose fractions isolated from sorghum bran were investigated and compared with cuticular content isolated from apple and tomato peel samples. Total cuticular contents in apple and tomato peels were the highest, ranging from 54.5 % to 54.8 %, when compared with the total cuticular content of maize, wheat and sorghum brans. Among three cereal samples, the cuticular material content in sorghum bran (7.14%) was higher than the maize bran and wheat bran (3.92% and 5.92% respectively). The hexadecanoic acid (C16), octadecanoic acid (C18), ω-hydroxy fatty acids, with medium chain functional groups such as enoic, epoxy and hydroxyl groups were identified in each cutin sample. The percentage of p-coumaric acid in apple and tomato peel samples were 84.0% and 78.7% respectively of the total phenolic acids present. The ferulic acid content in maize, sorghum and wheat brans were 94.1%, 92.8% and 88.0% respectively, indicating that ferulic acid was the major phenolic compound in these brans.

Identification of Adulterants in Chili Powder Based on the Histogram of Oriented Gradients Algorithm by Using an Electronic Nose

Driven by economic interests, adding adulterations in chili powder is a problem which threatens people’s health. Thanks to its nondestructive, rapid, and portable advantages, electronic nose has more potential to be used for adulteration detection than the traditional methods. An approach for identifying the adulterants in chili powder was proposed in this paper. Firstly, an electronic nose system with 10 gas sensors was designed, and then the response images were drawn based on the response signals of the electronic nose. Afterwards, gas features were extracted from those response images by using a histogram of oriented gradients (HOG) algorithm. Finally, an SVM-based identification model was constructed to achieve the identification of plant adulterants in chili powder. The experimental results showed that the identification accuracy of the adulterant categories (almond shell, red beetroot, and tomato peel) based on the HOG features could reach up to 98.3%, and the identification results for adulterant content were 94.2%, 93.3%, and 95%, respectively. Furthermore, in order to compare the efficiency of the proposed identification approach, the widely used model AlexNet was also investigated and discussed.