Preserving sensory attributes of roasted peanuts using edible coatings

Microencapsulation of peanut skin polyphenols for shelf life improvement of sunflower seeds

Derived from industrial processing waste, peanut skins contain polyphenols that delay oxidative food spoilage. However, these compounds are susceptible to light, heat, and oxygen exposure. Microencapsulation provides a solution by offering protection from these factors. The aim of this study was to evaluate the protective effect of peanut skin extract microcapsules on the chemical, microbiological, and sensory property and shelf life of sunflower seeds during storage. Five roasted sunflower seed samples were prepared: control (S-C); added with butylhydroxytoluene (S-BHT); coated with carboxymethyl cellulose (S-CMC); coated with CMC and the addition of peanut skin crude extract (S-CMC-CE); coated with CMC and the addition of microcapsules (S-CMC-M20). Sensory acceptability was determined using hedonic testing. Chemical (peroxide value, conjugated dienes, hexanal and nonanal content, and fatty acid profile), microbiological, and descriptive analyses were carried out on samples stored for 45 days at room temperature. Shelf life was calculated using a simple linear regression. All samples were microbiologically fit for human consumption and accepted by consumer panelists, scoring above five points on the nine-point hedonic scale. S-CMC-M20 exhibited the lowest peroxide value (6.59 meqO2/kg) and hexanal content (0.4 µg/g) at the end of the storage. Estimated shelf life showed that S-MC-M20 (76.3 days) extended its duration nearly ninefold compared to S-C (8.3 days) and doubled that of S-CMC-CE (37.5 days). This indicates a superior efficacy of microencapsulated extract compared to its unencapsulated form, presenting a promising natural strategy for improving the shelf life of analogous food items. PRACTICAL APPLICATION: Incorporating peanut skin extract microcapsules in coating sunflower seeds presents a promising strategy to extend the shelf life of lipid-rich foods, capitalizing on the antioxidant properties of polyphenols. This innovative approach not only enhances nutritional quality but also addresses sustainability concerns by repurposing agro-industrial byproducts, such as peanut skins. By meeting consumer demand for functional foods with added health benefits, this technique offers potential opportunities for the development of novel, value-added food products while contributing to circular economy principles and waste management efforts.

Improving the Shelf Life of Peeled Fresh Almond Kernels by Edible Coating with Mastic Gum

Coating, as a process in which fruits, vegetables, kernels, and nuts are covered with an edible layer, is an environmentally friendly alternative to plastic wrapping, which has been considered the most effective way to preserve them over the long term. On the other hand, prolonging the shelf life results in a reduction of spoilage and therefore achieving a goal that is very important nowadays—the reduction of food waste. The quality of preserved almonds kernels depends on factors such as grain moisture, storage temperature, relative humidity, oxygen level, packaging, and the shape of the stored nuts (along with being peeled, unpeeled, roasted, etc.). The commercial importance of the almond fruit is related to its kernel. Almonds that are peeled (without the thin brown skin) and stored have a shorter shelf life than unpeeled almonds since the reddish-brown skin, rich in antioxidants, may protect the kernels against oxidation. In this study, a bioactive edible coating has been tested, which may provide an effective barrier against oxygen permeation and moisture, thus preserving the quality of peeled fresh almonds by extending their shelf life. Mastic gum, as a natural coating agent, was used to coat the peeled fresh almond kernels in four different concentrations (0.5%, 1.0%, 1.5%, and 2.0% w/v). The effect of mastic gum coating on the quality parameters of the peeled fresh almonds (moisture uptake, oil oxidation, total yeast and mold growth, and Aspergillus species development) was studied during four months of storage. The results showed that mastic gum, as a coating agent, significantly (p < 0.05) reduced moisture absorption, peroxide and thiobarbituric acid indices, total yeast and mold growth, and Aspergillus species development in the peeled and coated fresh almonds, compared to the control, i.e., uncoated fresh almonds, during 4 months of storage, packed at room temperature (25–27 °C) inside a cabinet at 90% humidity. Therefore, mastic gum can be used as a great natural preservative coating candidate with antioxidant and antimicrobial effects.

Edible Coating from Enzymatically Reticulated Whey Protein-Pectin to Improve Shelf Life of Roasted Peanuts

Edible coatings are a viable alternative method to enhance food shelf life that can be designed using different biopolymers. This study evaluated the effect of a whey protein–pectin coating reticulated by microbial transglutaminase (mTG) on improving roasted peanuts’ shelf life. Peroxide value, water content, peanut color, and the solution’s contact angle were studied. The latter was improved by the presence of the enzyme. The results showed that the presence of the coating on the peanut surface reduces the peroxide value and water content, probably as a consequence of an improved barrier effect due to the presence of mTG, which protects the kernel. Enzymatically reticulated whey protein–pectin coatings are a promising alternative to enhance the shelf life of roasted peanut kernels using natural ingredients.

Edible packaging: Sustainable solutions and novel trends in food packaging

Novel food packaging techniques are an important area of research to promote food quality and safety. There is a trend towards environmentally sustainable and edible forms of packaging. Edible packaging typically uses sustainable, biodegradable material that is applied as a consumable wrapping or coating around the food, which generates no waste. Numerous studies have recently investigated the importance of edible materials as an added value to packaged foods. Nanotechnology has emerged as a promising method to provide use of bioactives, antimicrobials, vitamins, antioxidants and nutrients to potentially increase the functionality of edible packaging. It can act as edible dispensers of food ingredients as encapsulants, nanofibers, nanoparticles and nanoemulsions. In this way, edible packaging serves as an active form of packaging. It plays an important role in packaged foods by desirably interacting with the food and providing technological functions such as releasing scavenging compounds (antimicrobials and antioxidants), and removing harmful gasses such as oxygen and water vapour which all can decrease products quality and shelf life. Active packaging can also contribute to maintaining the nutritive profile of packaged foods. In this review, authors present the latest information on new technological advances in edible food packaging, their novel applications and provide examples of recent studies where edible packaging possesses also an active role.

Oxidative Stability of Protease Treated Peanut with Reduced Allergenicity

Oxidative stability and allergenicity are two major concerns of peanuts. This study evaluated the impact of protease treatment of peanuts on its oxidative stability during storage. The raw and dry-roasted peanut kernels were hydrolyzed with Alcalase solution at pH 7.5 for 3 h. The contents of Ara h 1, Ara h 2, and Ara h 6 in peanuts were determined before and after enzyme treatment by a sandwich ELISA. After drying, the samples were packed in eight amber glass jars and stored at 37 °C for 1-8 weeks. Controls are untreated raw and dry-roasted peanuts packed and stored in the same way as their treated counterparts. Samples were taken biweekly to determine peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) as indicators of oxidation (n = 3), and to determine antioxidant activity. Alcalase treatment reduced intact major allergens Ara h 1, Ara h 2, and Ara h 6 by 100%, 99.8%, and 85%, respectively. The PVs of Alcalase-treated raw and roasted peanuts was lower than those of untreated (p < 0.05) over the 8-week storage. The TBARS of Alcalase-treated raw peanuts were slightly higher than that of untreated (p < 0.05), but the TBARS of Alcalase-treated dry-roasted peanuts were slightly but significantly lower than that of untreated (p < 0.05). The protease treatment increased the antioxidant activities including reducing power, DPPH free radical scavenging capacity, and metal chelating capacity of peanuts.

A Natural Peanut Edible Coating Enhances the Chemical and Sensory Stability of Roasted Peanuts

This study aims to assess the enhancement of the chemical and sensory properties of roasted peanuts during storage, through the application of high-protein defatted peanut flour (DPF) coatings incorporated with and without antioxidants. The control sample without coating, packed in normal atmosphere (control), showed the highest conjugated dienes (CD) increment (from 1.17 on day 0 to 3.60 on day 180). Roasted peanuts without coating, packed in high barrier bags under vacuum, reached the lowest CD at day 180 (1.92). Conjugated trienes and peroxide values were analogous to CD. The control exhibited the greatest decrease in α-tocopherol (from 27.65 mg/100 g on day 0 to 21.32 mg/100 g on day 180) and γ-tocopherol (from 21.91 mg/100 g on day 0 to 14.99 mg/100 g on day 180). 3-Methylpyridine and 2,5-dimethylpyrazine decreased with storage time only for the control, which had the highest increase in oxidized flavor (from 0 on day 0 to 13.30 on day 180), cardboard (from 7.67 on day 0 to 15.23 on day 180), and astringency. The lowest decreases in roasted peanutty scores were seen in coated samples. DPF coatings delayed roasted peanuts oxidation, enhancing their sensory properties and shelf life compared with the control sample. PRACTICAL APPLICATION: Defatted peanut flour (DPF) is a byproduct obtained during peanut oil extraction and is a possible material for edible film preparation. This strategy adds value to the peanut industry by transforming a by-product into a material with the potential to develop biodegradable and economical films. The application of this DPF-based edible coating on the surface of roasted peanuts may have contributed to extent product's shelf life, allowing for coated products to be packaged in lower barrier and less expensive materials. Use of peanut material to coat peanuts avoids the risk of allergen protein cross contamination, which would be highly valuable for the food industry.

The Importance of Sensory Lexicons for Research and Development of Food Products

A lexicon is a set of standardized vocabularies developed by highly trained panelists for describing a wide array of sensory attributes present in a product. A number of lexicons have been developed to document and describe sensory perception of a variety of food categories.The current review provides examples of recently developed sensory lexicons for fruits and vegetables; grains and nuts; beverages; bakery, dairy, soy and meat products; and foods for animals. Applications of sensory lexicons as an effective communication tool and a guidance tool for new product development processes, quality control, product improvement, measuring changes during product shelf life, and breeding new plant cultivars are also discussed and demonstrated through research in the field.

Sensory and Chemical Stabilities of High-Oleic and Normal-Oleic Peanuts in Shell During Long-Term Storage

Oxidative rancidity is one of the major causes of peanut quality deterioration. The in-shell nut industry's greatest concern is to preserve high quality and extended the shelf life of these products. This research determined the sensory and chemical stabilities of raw in-shell high-oleic and normal-oleic peanuts during long-term storage. In-shell peanuts samples of normal- and high-oleic types were stored at room temperature (23 °C) for 675 days. The quality parameters, like the fatty acid composition, moisture content, free fatty acids (FFA), peroxide value (PV), conjugated dienes (CD), and p-anisidine value (pAV), as well as sensory attributes, were analyzed every 45 days. High-oleic samples showed a 4.36-fold higher oleic acid/linolenic acid (O/L) ratio (O/L = 10.65) than normal-oleic peanuts (O/L = 2.44). FFA, PV, CD, pAV, and oxidized and cardboard flavors increased in all stored samples but especially in normal-oleic peanuts. Conversely, roasted peanutty flavor decreased in all samples during storage but in lower proportion in high oleic peanut samples. The sensory and chemical changes that occurred in unshelled normal- or high-oleic peanut samples were not remarkable, suggesting that the shell may protect peanut kernels against deterioration. However, in-shell high-oleic samples show greater stability and shelf life than normal-oleic peanuts under the studied storage condition.

PRACTICAL APPLICATION

Quality preservation of peanuts is important for the food industry using peanuts as an ingredient. Peanut processors are concerned as to the best ways to preserve peanut quality for long-term storage. Raw high oleic peanuts kept in the shells show better preservation of their sensory and quality properties during storage. In-shell peanuts constitute an appropriate alternative to preserve chemical and sensory properties of this product.

Thyme and basil essential oils included in edible coatings as a natural preserving method of oilseed kernels

BACKGROUND

Sunflower seeds are susceptible to developing rancidity and off-flavours through lipid oxidation. Edible coatings and essential oils have proven antioxidant properties in different food products. The purpose of this study was to evaluate the combined effect of using an edible coating and thyme and basil essential oils to preserve the chemical and sensory quality parameters of roasted sunflower seeds during storage.

RESULTS

50% DPPH inhibitory concentration (IC50) values of 0.278 and 0.0997 µg mL(-1) were observed for thyme and basil, respectively. On storage day 40, peroxide values were 80.68, 70.28, 68.43, 49.31 and 33.87 mEq O2 kg(-1) in roasted sunflower seeds (RS), roasted sunflower seeds coated with carboxymethyl cellulose (CMC) (RS-CMC), roasted sunflower seeds coated with CMC added with basil (RS-CMC-A), thyme (RS-CMC-T) and butylated hydroxytoluene (RS-CMC-BHT), respectively. RS-CMC-T and RS-CMC-BHT presented the lowest peroxide values, conjugated dienes and p-anisidine values during storage. RS-CMC-BHT, RS-CMC-T, and RS-CMC-A showed the lowest oxidized and cardboard flavour intensity ratings. On storage day 40, roasted sunflower flavour intensity ratings were higher in RS-CMC-T and RS-CMC-A.

CONCLUSIONS

Thyme and basil essential oils added to the CMC coating improved the sensory stability of this product during storage, but only thyme essential oil increased their chemical stability.

Chemical and Sensory Quality Preservation in Coated Almonds with the Addition of Antioxidants

Almonds provide many benefits such as preventing heart disease due to their high content of oleic fatty acid-rich oil and other important nutrients. However, they are susceptible to oxidation reactions causing rancidity during storage. The objective of this work was to evaluate the chemical and sensory quality preservation of almonds coated with carboxymethyl cellulose and with the addition of natural and synthetic antioxidants during storage. Four samples were prepared: almonds without coating (C), almonds coated with carboxymethyl cellulose (CMC), almonds coated with CMC supplemented with peanut skins extract (E), and almonds coated with CMC and supplemented with butylhydroxytoluene (BHT). Proximate composition and fatty acid profile were determined on raw almonds. Almond samples (C, CMC, E and BHT) were stored at 40 °C for 126 d. Lipid oxidation indicators: peroxide value (PV), conjugated dienes (CD), volatile compounds (hexanal and nonanal), and sensory attributes were determined for the stored samples. Samples showed small but significant increases in PV, CD, hexanal and nonanal contents, and intensity ratings of negative sensory attributes (oxidized and cardboard). C had the highest tendency to deterioration during storage. At the end of storage (126 d), C had the highest PV (3.90 meqO2 /kg), and BHT had the lowest PV (2.00 meqO2 /kg). CMC and E samples had similar intermediate PV values (2.69 and 2.57 meqO2 /kg, respectively). CMC coating and the addition of natural (peanut skin extract) and synthetic (BHT) antioxidants provide protection to the roasted almond product.

Antioxidant effects of the monoterpenes carvacrol, thymol and sabinene hydrate on chemical and sensory stability of roasted sunflower seeds

BACKGROUND

Oxidation products and rancid flavors decrease the sensory quality of food products, making them unacceptable to consumers. Synthetic antioxidants are used in many foods to prevent rancidity, though their safety is questioned. Monoterpenes are obtained from essential oils and many of them have shown antioxidant activity. The objective of this study was to evaluate the stability of sensory and chemical parameters in roasted sunflower seeds supplemented with carvacrol, thymol and sabinene hydrate monoterpenes.

RESULTS

Five samples were prepared: control roasted sunflower seeds (RS-C) and sunflower seeds treated with carvacrol (RS-Car), sabinene hydrate (RS-S), thymol (RS-T) and butylated hydroxytoluene (RS-BHT). The three monoterpenes (carvacrol, sabinene hydrate and thymol) provided protection to this food product, inhibiting the formation of oxidative deterioration compounds such as peroxides and hexanal and undesirable off-flavors such as oxidized and cardboard flavors. Sabinene hydrate had greater effect preventing peroxide formation during storage than the other monoterpenes.

CONCLUSION

Carvacrol, sabinene hydrate and thymol could be used as an alternative to synthetic antioxidants for preserving the quality of roasted sunflower seeds.