Effects of Pomegranate Peel Extract and/or Lactic Acid as Natural Preservatives on Physicochemical, Microbiological Properties, Antioxidant Activity, and Storage Stability of Khalal Barhi Date Fruits

Abstract

The use of natural preservatives in the storage of fresh fruits is a promising approach to healthier and more sustainable food processing. The current study was conducted to evaluate the effect of pomegranate peel extract (PPE) and lactic acid (LA) as natural preservatives on the shelf life of Khalal Barhi date fruits. Physicochemical properties, antioxidant activity, color parameters, texture profile, sensory characteristics, and microbiological quality of date fruits were evaluated during six weeks of cold storage (4 ± 1 °C). The bioactive compounds in PPE were determined by HPLC analysis, which showed that PPE is a rich source of bioactive compounds, particularly phenolics and flavonoids. The results exhibited decreased moisture content (from 68.36–68.43 to 62.13–63.11%) and an increased soluble solids content (from 27.16–27.24 to 31.45–33.91%) in all samples with prolonged storage. Likewise, a slight decrease in the pH (from 6.00–6.28 to 4.89–5.29) with an increase in acidity (from 0.12–0.14 to 0.23–0.27%) during storage was observed. Generally, treated samples showed lower changes in moisture content, soluble solids content, pH, and acidity than the control. A decrease in total phenolic content (TPC) (from 8.22–12.36 to 3.19–5.17 mg GAE/g) and antioxidant activity (from 44.11–68.26 to 23.84–38.52%) of all samples was observed with progressed storage, meanwhile, the treatment with PPE significantly (p < 0.05) increased TPC with a concomitant increase in antioxidant activity and maintained higher values of both throughout storage. The results exhibited a decrease in L* (from 54.87–55.92 to 41.68–45.68) and b* (from 36.25–37.09 to 23.59–25.42) values of all samples, while the a* value of all samples increased (from 1.29–1.40 to 2.22–2.43) with storage. Dipping treatment in PPE solution improved the color, exhibited the lowest change in color parameters, and maintained better texture properties during storage. Similarly, sensory properties decreased (from 8.21–8.66 to 6.71–7.21) during storage with insignificant (p > 0.05) differences among samples. Dipping treatments inhibited the growth of yeasts and molds over time, with the lowest microbial count recorded in the PPE-treated samples. It can be concluded that PPE was found to have protective effects on Khalal Barhi date fruit quality by controlling post-harvest changes and lowering the microbial load.

Development, RSM-based modeling, and process optimization of an ultrasonic coating system for extending the storage life of fresh fruits

“…The ripening percentage (R p ) of the tested date samples of different treatments varied between 5.9 and 98.7%. As date palm is a climacteric crop, the fruits, after harvesting, are subjected to a series of maturity stages, including chemical and physiological changes, besides the production of the ethylene hormone, which is the main factor responsible for the ripening process (Alqahtani et al, 2023). As shown in the correlation analysis, GAC, DT, and ST exhibited significant effects (p < 0.05) on the R p , whereas Ct, AFR, HOL, LT, and Dt revealed insignificant effects (p > 0.05).…”

“…(1) the natural ripening processes of dates (the conversion from Khalal to Rutab and Tamr stage) include an increase in CO2 and ethylene production, which can lead to degradation of natural pigments and formation of a dark color (Alqahtani et al, 2023); (2) with prolonged storage, the conversion of sucrose to reducing sugars due to natural ripening process may contribute to the change in fruits' color into light brown (Siddiq et al, 2013); (3) the oxidative enzymes such as polyphenol oxidase, peroxidase, and catalase could be responsible for the discoloration and browning through the oxidation of endogenous phenols into quinones (Ghafoor et al, 2022;Taher et al, 2022). In the present study, the minor changes in ΔE* observed in coated samples with an optimized ultrasonic system reflect a delay in ripening, which could be due to the improved barrier properties of the developed coating and its ability to modify the respiration and ethylene production rates of dates, which, in turn, slowed down the fruit's metabolism (Asgarian et al, 2023).…”

“…Hilali, a common Saudi Arabian date variety, is mainly consumed at a partial maturity stage known as Khalal, where the fruits have a yellow color, crispy texture, and sweety taste. However, the rapid conversion of Hilali date fruits from Khalal to Rutab (soft, brown, and ripe fruits) due to its climacteric nature, as all date palm varieties, represents the major challenge after harvesting and during storage, handling, transportation, and exportation (Alqahtani et al, 2023). Although cold storage represents the most common technology on a commercial scale applied to reduce the quality changes of fresh fruits and vegetables, postharvest changes such as weight loss, shrinking, softening, odor changes, and fruit conversion from Khalal to Rutab are still high (Fawole et al, 2020).…”

Laser irradiation and pomegranate peel extract as novel trends to preserve the strawberry quality characteristics

“…In this regard, Jiang et al [46] reported that the coating of blue berries with chitosan did not affect negatively on the avor attribute. Alqahtani et al [47] found that the dipping of Barhi date fruits in PPE maintained sensory characteristics during storage period.…”

The Prospective Effect of Green Tea versus Pomegranate Peels Extracts on Submandibular Salivary Glands of Albino Rats after Methotrexate Administration (Histological and Immunohistochemical Study)

“…Powder was made from the freeze-dried samples by using a mincer (FOSS Cemotec minced, Germany), and the powder was stored at 40°C until usage. Dry powder was mixed with distilled water (50-g dry solids/100 mL) and stored at 4°C until utilized [20]. All groups of rats were abandoned 1 week after the experiment with no treatment.…”