Stability of Capsaicinoids and Antioxidants in Dry Hot Peppers under Different Packaging and Storage Temperatures

Analysis of changes in nutritional compounds of dried yellow chili after different processing treatments

Dried yellow chili is highly appreciated by consumers due to its excellent quality and flavor. The quality of products is determined by the drying and storage methods. In this study, dried yellow chilis were processed by natural air drying and hot air drying methods and then stored under three conditions: ambient temperature, ambient temperature with light avoidance, and at 10 °C with light avoidance for 12 months. The changes in the bioactive compounds during this period were analyzed attempting to reveal correlations between the different treatments and these compounds, with the aim of providing references for maintaining the bioactive compounds of pepper products. The results showed that samples treated with hot air had higher levels of fatty acids, resulting in a more pronounced flavor. During storage, samples stored at 10 °C with light avoidance were more effective in preserving soluble solids, total protein content, total phenols, capsaicinoids and most fatty acids.

Effects of moisture content and packaging on color stability of red pepper (Capsicum annuum L.) powder

The color stability and quality changes of red pepper powder of various initial moisture content (7%, 10%, and 13%) and packaged with different materials, low-density polyethylene (LDPE) and nylon layered polyethylene (Ny/PE) film pouches or plastic and glass bottles, were compared during storage at 20 °C for 126 days. In the 7% moisture content sample packaged in LDPE film and plastic bottles, the L* and b*-values increased from 48.2 ± 0.7 and 15.4 ± 1.1 to 65.2-65.9 and 29.5-30.3, respectively, while the a*-value decreased from 26.1 ± 0.7 to 14.2-15.9, indicating a noticeable color change from red to orange. However, the decrease in the capsaicinoid and free sugar content of red pepper powder over time was found to have no significant correlation with moisture content and packaging type. As a result, the color change during the long-term storage of red pepper powder was greatly influenced by the initial moisture content and gas permeability of the packaging material.

Effect of packaging materials and storage duration on the functional quality of red hot peppers (Capsicum annum L.) pods

The preservation of the functional quality of red pepper requires appropriate packaging materials, storage duration, and condition. This study evaluated the effect of the packaging materials and the storage duration on the functional quality of the red hot pepper pod for ten months at ambient storage temperature (25±2 °C) in four packaging materials: Jute sacks, Fertilizer Liner Sheet (FLS), Fertilizer Woven Polypropylene + Liner Sheet (FWPP + LS), and PICS bags (Purdue Improved Crop Storage) using two-factor factorial designs. The samples were analyzed at two-month intervals for water activity (aw, extractable color, total phenolic compounds, pungency index and oleoresin content. Except for aw, other functional qualities of red hot pepper degrade with advanced storage in all packaging materials. At the end of storage, the maximum values of aw (0.76) and the minimum values of aw (0.38) were recorded in jute sacks and PICS bags. Extractable color (ASTA units) decreased from 225.42 to 133.11, 228.71-139.09, 274.29-171, and 288.91-218.98 in jute bags, FLS, FWPP + LS, and PICS bags, respectively. Phenolic compounds (GAE mg/g dry samples) degraded from 2.32 to 1.02, 2.33-1.37, 2.4-1.35, and 2.59-1.85 in jute bags, FLS, FWPP + LS and PICS bags, respectively. The pungency index (Abs/g dry samples) of the samples changed from 4.55 to 2.56, 5.49-4.00, 5.00-3.49, and 4.74-2.72 in jute bags, FLS, FWPP + LS, and PICS bags, respectively. The oleoresin content (%) decreased from 12.88 to 7.18, 12.92-7.78, 13.19-8.45 and 13.58-9.88 in jute sacks, FLS, FWPP + LS and PICS bags, respectively. The study revealed that the PICS bags retained the highest functional qualities compared to other packaging materials.

Effect of storage on bioactivity of an Algerian spice "paprika": optimization of phenolic extraction and study of antioxidant and antibacterial activities

The effect of different storage methods (ambient temperature (A), refrigeration at 4 °C (R) and freezing at - 18 °C (F)), on the phytochemistry of an Algerian spice (paprika powder), was assessed. The optimized extract was obtained under the optimum conditions of ultrasound-assisted extraction (UAE) using response surface methodology (RSM) coupled with a Box-Behnken Design (BBD). This extract was evaluated for its total phenolics content (TPC), total flavonoids content (TFC) and its antioxidant and antibacterial activities. Under the optimum conditions (5 min for the irradiation time, 40% for the amplitude, 80% for ethanol concentration and 50% for solid-liquid ratio) the TPC was 12.23 ± 1.01 mg Gallic Acid Equivalent/gram of Dried Powder (mg GAE/g DP) which is very close with experimental assay. The TPC are better preserved at A whereas TFC and the antioxidant activity at F, and the antibacterial activity depend on the storage methods and the strains tested.

Post-harvest profile, processing and value addition of dried red chillies (Capsicum annum L.)

Chilli has dominated and retained an important place amongst the spices worldwide. They are dried ripe fruits intuitively consumed as a spice, condiment, culinary, and medicinal purposes. The global consumption pattern is intriguing because of the inherent pungency, aroma, taste, spicy flavour, and therapeutic properties. Predominantly, the colour and pungency decide the quality features and are actively responsible for organized marketing and trade of the dried chillies. India is one of the leading producers and exporters of chilli. The chemical composition of the chillies varies substantially with agro-climatic zones and post-harvest management strategies. The quantum of post-harvest loss of 25-35% hampers the farmer's income and affects the wholesale/retail marketing. This review paper is intended to provide a deep insight into the advancements in various post-harvest unit operations of dried red chillies. A detailed overview of post-harvest operations (drying, grading, destalking, packaging, storage) and processing techniques for value-added products (chilli powder, dried flakes, seeds, oleoresin) is discussed in this paper. The presented information will help the researchers and the industry personnel engaged in the post-harvest processing and value addition of dried red chillies.

Graphical abstract

Effects of packaging and temperature abuse on the quality of red pepper (Capsicum annuum L.) powder

Storage stability of pepper (Capsicum annuum L.) powder packaged using 2 different film pouches of Ny/PE and PET/Al/PE inserted with moisture absorbent and oxygen scavenger was investigated during storage at 25 °C for 5 months and at 40 °C for 14 days. The moisture content of red pepper powder did not change significantly in PET/Al/PE packaging but decreased significantly in Ny/PE packaging after the abuse of storage temperature. The color of red pepper powder was quite stable in all packaging treatments. Other quality characteristics of all packaged pepper powder, including microbial cell count, capsaicinoids, ascorbic acid, and free sugar content, were also maintained near their initial levels with no appreciable changes during storage. Red pepper powder with a moisture content of 13-14% and packaged with a film with high gas-barrier properties can be stored for more than 5 months even if there is an unexpected temperature abuse during storage.

Antifungal Potential of Capsaicinoids and Capsinoids from the Capsicum Genus for the Safeguarding of Agrifood Production: Advantages and Limitations for Environmental Health

Opportunistic pathogenic fungi arise in agricultural crops as well as in surrounding human daily life. The recent increase in antifungal-resistant strains has created the need for new effective antifungals, particularly those based on plant secondary metabolites, such as capsaicinoids and capsinoids produced by Capsicum species. The use of such natural compounds is well-aligned with the One Health approach, which tries to find an equilibrium among people, animals, and the environment. Considering this, the main objective of the present work is to review the antifungal potential of capsaicinoids and capsinoids, and to evaluate the environmental and health impacts of biofungicides based on these compounds. Overall, capsaicinoids and their analogues can be used to control pathogenic fungi growth in plant crops, as eco-friendly alternatives to pest management, and assist in the conservation and long-term storage of agrifood products. Their application in different stages of the agricultural and food production chains improves food safety, nutritional value, and overcomes antimicrobial resistance, with a lower associated risk to humans, animals, and the environment than that of synthetic fungicides and pesticides. Nevertheless, research on the effect of these compounds on bee-like beneficial insects and the development of new preservatives and packaging materials is still necessary.

The Vacuum and Light-Avoided Packaging Ameliorate the Decline in Quality of Whole Chili during Storage

Vacuum packaging is a superior procedure that could maintain the quality of dried red peppers for a relatively longer period, while the effect of light avoidance was inconsistent. Therefore, this study was to evaluate the effect of vacuum in combination with light avoidance on the storage quality of peppers and to investigate vacuum packaging and vacuum and light-avoided packaging influence the quality characteristics of dried chili peppers during storage. The results indicated that the quality characteristics of peppers gradually deteriorated: redness, extractable color, capsanthin, capsaicinoids, pungency, total phenolic content, and antioxidant capacity decreased, whereas moisture, water activity, and browning index increased as storage progressed. Vacuum packaging inhibited these changes compared with the control. Vacuum and light-avoided packaging further decelerated the quality loss of dried peppers, with the minimum changes in color, pungency, and antioxidant capacity of dried peppers during storage, and these could be due to lower water activity by light avoidance. Therefore, light avoidance may be necessary to further delay the deterioration of dried peppers under vacuum, and vacuum and light-avoided packaging could better retain the quality of dried chili peppers.

Effect of three natural antioxidants on the structure and physicochemical properties of sweet potato starch noodles

The study aimed to investigate the effect of three kinds of natural antioxidants (NAs), such as curcumin, tea polyphenols (TP), and lycopene, on sweet potato starch's structure and physicochemical properties of starch noodles. We found that the broken rates, iodine blue values, hardness, and chewiness of natural antioxidant starch noodles (NASN) were increased with the addition of the NAs. Additionally, the elasticity decreased with the addition of curcumin and lycopene, but it increased with the addition of TP. The cross-section structure of NASN obtained by scanning electron microscope (SEM) showed more holes appeared when adding NAs, and the additional amount had a pronounced effect on the microstructure of starch noodles (SN) regardless of the kind of NA added. The X-ray diffraction detection showed that some crystal forms were significantly damaged, and the addition of NAs affected the crystallization process of starch and produced a small proportion of new crystals in the NASNs. The protective effects of SN on NAs and their antioxidant capacities under dry and room temperature storage (DRTS) and wet and frozen storage (WFS) conditions were optimal as compared to those of flour noodles (FN). The results showed that adding NAs could improve the sensory quality and antioxidant function of starch noodles. In turn, the dense structure of starch noodles can also have a significant protective effect on antioxidants and their antioxidant activities, which is especially obvious under WFS conditions.

Non-destructive prediction of the hotness of fresh pepper with a single scan using portable near infrared spectroscopy and a variable selection strategy

There has been no study on using near-infrared spectroscopy (NIRS) to predict the hotness of fresh pepper. This study is aimed at developing a non-destructive and accurate method for determining the hotness of fresh peppers using portable NIRS and the variable selection strategy. Spectra from different locations on samples were obtained non-destructively with a single scan. Quantitative models were established using partial least squares (PLS) with a variable selection method or fusion method. The results showed that near-stalk was the best spectral acquisition location for quantitative analysis. The variable selection strategy allows the selection of targeted characteristic variables and improves the results. A fusion method, namely variable adaptive boosting partial least squares (VABPLS), was selected for optimal prediction of the performance. In the optimized model, the root mean square errors of prediction for the validation set (RMSEPvs) of capsaicin, dihydrocapsaicin and pungency degree were 0.295, 0.143 and 47.770, respectively, while the root mean square errors of prediction for the prediction set (RMSEPps) collected one month later were 0.273, 0.346 and 75.524, respectively.

Agronomic Performance, Capsaicinoids, Polyphenols and Antioxidant Capacity in Genotypes of Habanero Pepper Grown in the Southeast of Coahuila, Mexico

The genetic improvement program of the Seed Technology Training and Development Center works on the agronomic characterization and the content of bioactive compounds in eight genotypes of habanero pepper. The objective is to select genotypes with good agronomic performance that allow the generation of inbred lines to obtain hybrids. In this study, the agronomic performance and the content of bioactive compounds (capsaicinoids, polyphenols, and antioxidant capacity) were evaluated in eight genotypes of habanero pepper grown in the southeast of Coahuila, Mexico, identified as HNC-1, HNC-2, HNC-3, HNC-4, HNC-5, HNC-6, HNC-7, and HCC-8. The plants were grown in a greenhouse for 127 days, under a completely randomized design with four replications each. The results revealed that the yield (g·plant−1) and number of fruits per plant did not show significant differences between genotypes. However, for the fruit length, the genotypes HCC-8, HNC-7, HNC-6, and HNC-5 stood out with over 40 mm, while in equatorial diameter of the fruit, HCC-8, HNC-4, and HNC-2 stood out with 26.45, 26.46, and 25.12 mm, respectively. The results of the chemical analyses allowed us to identify that HNC-5 and HNC-6 had the highest capsaicin concentration (931.38 and 959.77 mg·kg−1), dihydrocapsaicin (434.95 and 445.89 mg·kg−1), Scoville Heat Units greater than 210,000, total phenols (67.54 and 71.15 mg/100 g) and total flavonoids (34.21 and 38.29 mg/100 g), respectively. The HNC-1 and HNC-6 genotypes had the highest carotenoids concentration with 103.96 and 105.07 mg/100 g, and HCC-8 registered the highest anthocyanin content with 22.08 mg C3GE/100 g. The antioxidant capacities showed significant differences (p ≤ 0.05) between genotypes, with a range of 43.22 to 110.39 µmol TE/100 g, 72.37 to 186.56 µmol TE/100 g, and 191.41 to 244.98 µmol TE/100 g for the tests of DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), and FRAP (ferric reducing antioxidant power). The results of this research will be used to select habanero pepper genotypes that can be used in genetic improvement programs to increase the productive potential and the content of bioactive compounds in the fruits to expand their applications in the food industry.

Factors affecting the capsaicinoid profile of hot peppers and biological activity of their non-pungent analogs (Capsinoids) present in sweet peppers

Capsaicinoids are acid amides of C₉-C₁₁ branched-chain fatty acids and vanillylamine and constitute important chemical compounds of Capsicum annuum together with their non-pungent analogs (capsinoids) which have an impressive list of health benefit properties (i.e., analgesia, anti-obesity, thermogenic, cardiovascular, gastrointestinal, antioxidant, anti-bacterial, anti-virulence, anti-inflamatory, anti-diabetic, inhibits angiogenesis, and improves glucose metabolism) . In this review, the state of art on how capsaicinoids are affected by different pre- and postharvest factors is discussed together with their biological activity. For instance, high light intensity and heat treatments may reduce capsaicinoid content in fruits probably due to the loss of activity of capsaicin synthase (CS) and phenylalanine ammonia lyase (PAL). The pungency in peppers varies also with environment, genotype or cultivar, node position, fruiting and maturity stages, nitrogen and potassium contents. As the fruit mature, capsaicinoid levels increase. Fruits from the second node tend to have higher accumulation of pungency than those of other positions and the pungency decreases linearly as the node position increase. Sodium hydroxide treatment reduces the pungency of pepper fruit as it hydrolyzes and modifies one of the features (vanillyl group, the acid-amide linkage and alkyl side chain) of capsaicin molecule. Salt and water stress increase PAL and capsaicin synthase activity and increase the capsaicinoid accumulation in fruit, by negatively regulating peroxidase activity at appropriate levels. Future research must be directed in better understanding the changes of capsinoids during pre and post-harvest management, the causal drivers of the loss of activity of the aminotransferase gene (pAMT) and if possible, studies with genetically modified sweet peppers with functional pAMT. Available data provided in this review can be used in different agricultural programs related to developing new cultivars with specific pungency levels. The contents of capsaicinoids and capsinoids in both fresh fruits and marketed products are also of remarkable importance considering the preferences of certain niches in market where higher added-value products might be commercialized.

Irradiation Maintains Functional Components of Dry Hot Peppers (Capsicum annuum L.) under Ambient Storage

Hot peppers used as natural flavoring and coloring agents are usually irradiated in prepacked form for decontamination. The effects of gamma radiation on the stability of functional components such as capsaicinoids and antioxidant compounds (carotenoids, ascorbic acid and total phenolics) were investigated in hot peppers (Capsicum annuum). Whole dried peppers packed in polyethylene bags were gamma irradiated at 0 (control), 2, 4, and 6 kGy and subsequently stored at 25 °C for 90 days. The irradiation dose did not substantially affect the initial contents of capsaicinoids, ascorbic acid and total phenolics, though the concentration of carotenoids declined by 8% from the control (76.9 mg/100 g) to 6 kGy radiation dose (70.7 mg/100 g). Similarly, during storage for 90 days at ambient temperature the concentrations of capsaicinoids and total phenolics remained fairly stable with mean percent reductions from 3.3% to 4.2%, while the levels of total carotenoids and ascorbic acid significantly (p < 0.05) declined by 12% and 14%, respectively. Overall, neither irradiation nor subsequent ambient storage could appreciably influence the contents of functional components in hot peppers. These results revealed that gamma irradiation up to 6 kGy can be safely used for decontamination to meet the needs for overseas markets without compromising product quality.