Effect of alginate coating enriched with Shirazi thyme essential oil on quality of the fresh pistachio (Pistacia vera L.)

Abstract

In this study, different concentrations of alginate (0%, 1% and 1.5% w/v) enriched with various concentrations of Shirazi thyme (Zataria multiflora Boiss) essential oil (0%, 0.3% and 0.5% w/v), were examined on postharvest characteristics of the fresh pistachio. The measurements (including total phenolic compounds, antioxidant capacity, free fatty acid, peroxide value, aerobic mesophilic bacteria, mold and yeast, saturated and unsaturated fatty acids) were performed after 0, 13, 26 and 39 days during storage (3 ± 1 °C, 80 ± 5% RH). The results showed that alginate edible coating enriched with thyme's essential oil (EO), contributed to the maintenance of higher values of phenolic content and antioxidant activity in comparison with the control. Edible coating treatment of enriched alginate with thyme oil reduced mold and yeast growth compared to the control and the alginate without thyme oil. Peroxide value and free fatty acid content were significantly lower in fruits treated with alginate-thyme in comparison with the control. All fruits which had been treated with alginate-thyme EO showed lower changes in saturated and unsaturated fatty acids after 39 days of storage, and fruits coated with combination of 1% alginate and 0.3% EO showed the highest content of palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, compared with other treatments.

Impact of carboxymethyl cellulose coating enriched with Thymus vulgaris L. extract on physicochemical, microbial, and sensorial properties of fresh hazelnut ( Corylus avellana L.) during storage

“…As a result, the 1.0% extract in 1.5% CMC coating was the best choice for controlling the fungal growth of hazelnut. Our findings are in agreement with other research studies that stated that edible coatings and phenolic compounds in extract/essential oil reduced microbial contamination in coated nut (Azimzadeh & Jahadi, 2018; Hashemi et al, 2020; Kazemian‐Bazkiaee et al., 2020).…”

“…The MC of all samples, was less than the limit values, which gives a good indication of the coating performance on shelf life extension of hazelnuts. In fact, the coating acts as a barrier against the moisture and oxygen transfer to the hazelnut tissue (Hashemi et al, 2020; Martín et al., 2019). Coating thickness is an important factor in the transfer of water and gases, and it directly affects the biological properties and shelf life of coated nuts.…”

“…(2013), Martín et al. (2019), and Hashemi et al (2020), who reported the PV of nuts were increased over time, and coated samples were more stable in term of oil oxidation (Chlebowska‐Smigiel et al., 2008; Hashemi et al, 2020; Martín et al., 2019; Riveros et al., 2013). Similar results were observed by Haq et al.…”

“…Hazelnut ( Corylus avellana L.) is typically consumed as a whole nut or as an ingredient for bakery and confectionery industries as it is highly appreciated for its crunchy texture, typical taste, and aroma (Belviso et al., 2017). The fresh nut contains more moisture in fruit cells, compared to the conventionally dried nut and this major humidity makes it prone to fungi contamination and a faster rate of respiration, which can cause to decrease the fruit quality more quickly (Hashemi et al, 2020). Storage conditions affect the nut quality, and therefore, are care for both direct consumption and food industries (Sabaghi et al., 2015).…”

“…It includes interaction among food, packaging materials, or coating which preserve the quality, safety, and shelf life of product (Esfahani et al., 2020). Natural biodegradable polymers such as polysaccharide, protein, or lipid (Ekramian et al., 2020) based coatings prevent moisture loss, reduce the respiration rate and water evaporation, exclude oxygen transfer and microbial growth, ensuing in lipid stability, and maintained the quality of nuts (Hashemi et al, 2020; Kazemian‐Bazkiaee et al., 2020).…”