Quality of shredded carrots minimally processed by different dipping solutions

Evaluation of the Shelf life of Ready-to-Eat Fresh Bamboo Sprouts (Phyllostachys edulis) Packaged in a Modified Atmosphere or Vacuum: A Comparative Study

During the last decades, the consumption of bamboo sprouts (Phyllostacys edulis) has increased because they are considered a "superfood". However, this product is characterized by a short shelf life due to the deterioration in quality parameters. The aim of this study was to investigate the application of two modified atmosphere packaging (MAP) systems (MAP1: 2% O2, 5% CO2, 93% N2 and MAP2: 3% O2, 7% CO2, 90% N2) to fresh-shelled ready-to-eat bamboo sprouts and compare these packaging systems with vacuum packaging during storage for 28 days at 4 °C using heat-sealable polyamide and polyethylene (PA/PE) trays. Several chemical-physical parameters (moisture content, water activity, pH, headspace composition, and firmness) were monitored, as well as CIELab colorimetric parameters and microbial growth. The quantification of selected organic acids was performed via UHPLC. Mathematical kinetic models were applied to study the evolution of total phenol (TPC), flavonoid (TFC), and carotenoid content (TCC) during storage. The evolution of antioxidant potential investigated by ABTS, DPPH, and β-carotene bleaching tests was also assessed. Results showed that at the end of the storage period, significant variations in the colorimetric parameters are detectable between the sprouts apical portion and the basal one, regardless of both applied MAPs. A linear reduction in both DPPH and ABTS radical scavenging activity was evidenced during storage, regardless of the type of packaging applied. In DPPH test samples packaged in MAP after 28 days of storage, they retain good antioxidant activity, whereas in vacuum, this activity is reduced by 50% compared to the initial value (IC50 values from 24.77 to 32.74 μg/mL and from 24.77 to 71.12 μg/mL for MAP2 and vacuum, respectively).

Evaluation of the Efficacy of Antioxidant Extract from Lemon By-Products on Preservation of Quality Attributes of Minimally Processed Radish (Raphanus sativus L.)

The aim of this work was to enhance the use of a food-grade antioxidant extract obtained from lemon processing byproducts (peel, pulp and seeds) to extend the shelf life of minimally processed radishes. The extract (LPE) was previously characterized in terms of total phenolic (6.75 ± 0.34 mg GAE g-1 d.w.) and flavonoid content (2.04 ± 0.09 mg CE g-1 d.w.) and antioxidant activity, and eriocitrin and hesperidin were identified as the most prevalent phenolic compounds by a UHPLC system. The effects of different dipping aqueous solutions (UCR, DRa, DRb) and alginate-based edible coating formulations (CRc, CRd) with and without the antioxidant extract were studied on the quality parameters of minimally processed radishes, characterized regarding their microbiological and physicochemical characteristics for up to 14 days at 3 °C. The coating formulated with LPE delayed the radish respiration process, as well as resulting in less color variation (ΔE < 3) and reduced mesophilic aerobic count values (4.49 ± 1.43 log CFU g-1), proving the effectiveness of LPE as a value-added ingredient in developing post-harvest strategies to prolong the shelf life of minimally processed vegetables. Indeed, coated samples without the extract showed a clear development of rotting, which led to the end of their shelf life on their 7th day of storage.

Multi-Target Alternative Approaches to Promoting Fresh-Cut Carrots' Bioactive and Fresh-like Quality

Fresh-cut fruits and vegetables, as near-fresh foods, are a quick and easy solution to a healthy and balanced diet. The rapid degradation of nutritional and sensory quality during the processing and storage of a product is critical and plant-type-dependent. The introduction of disruptive technological solutions in fresh-cut processing, which could maintain fresh-like quality with less environmental impact, is an emerging research concept. The application of abiotic stress treatments (heat shock and UV-C) induces metabolic responses and microbial effects in plant tissues, potentially slowing down several quality senescence pathways. The previously selected combined and single effects of heat shock (100 °C/45 s; in the whole root) and UV-C (2.5 kJ/m²) treatments and two packaging conditions (oriented polypropylene (OPP) vs. micro-perforated OPP films) on controlling critical degradation pathways of fresh-cut carrots and on promoting bioactive and sensory quality during storage (5 °C, 14 days) were studied. Among the tested combinations, synergistic effects on the quality retention of fresh-cut carrots were only attained for applying heat shock associated with micro-perforated OPP film packaging. Its effects on reducing (3.3 Log₁₀ CFU/g) the initial contamination and controlling microbiological spoilage (counts below the threshold limit of 7.5 Log₁₀ CFU/g), increasing the bioactive content (38% and 72% in total phenolic content and chlorogenic acid, respectively), and preserving fresh quality attributes prove to be a viable alternative technology for shredded carrot processing.

Antimicrobial, sealable and biodegradable packaging to maintain the quality of shredded carrots and pineapple juice during storage

Increasing consumer demand for foods with high nutritional quality, prolonged shelf life and low environmental impact of the package, is driving innovation towards the development of new packaging. Multifunctional food packaging films, biodegradable, heat-sealable and antimicrobial, were developed. A PLA coating layer incorporating either sodium benzoate, potassium sorbate, or a combination of them was deposited onto a poly(lactic) acid/poly(butylene adipate-co-terephthalate) substrate film. The effectiveness of the developed systems to preserve the quality of foods was tested in shelf-life experiments performed on shredded carrots and pineapple juice, selected as model processed raw foods. The best performance was observed for the active film containing potassium sorbate: microbial populations increased less rapidly and were 0.7-1.8 log CFU/g lower at the end of storage period in this film than in control packs. Of the two model foods, the pineapple juice was better preserved: after 7 days in active packaging, color change and microbial counts of juice were below that of control, observed after one day and after 3 days of storage respectively. Moreover, the incorporation of the active phases did not significantly affect the mechanical, barrier and optical properties of the films, opening new ways to prolong shelf-life of minimally processed foods.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-022-05435-y.

Efficacy of Pectin-Based Coating Added with a Lemon Byproduct Extract on Quality Preservation of Fresh-Cut Carrots

The effect of an edible pectin-based coating supplemented with a lemon byproduct extract on the quality attributes of fresh-cut carrots was studied. Color, hardness, microbial growth, respiratory activity, and antioxidant properties of fresh-cut carrots were studied during 14 days of storage at 4 °C. The application of a pectin-based coating containing a lemon byproduct extract preserved carrots’ physiological parameters, reduced their physiological activity and, thus, delayed senescence. This aspect was also confirmed by the reduced O2 consumption of the coated carrots due to the slowing down of the product’s metabolic reactions. Moreover, coated carrots were characterized by limited changes in colour (ΔE < 3) and white-blush development on both cortical tissue and vascular cylinder, and the presence of calcium chloride in the coating formulation helped to maintain carrots’ hardness throughout storage. In addition, treatment with pectin-based coating and lemon byproduct extract improved microbiological stability of fresh-cut carrots, showing the lowest value of total bacterial count immediately after treatment (2.58 log CFU g−1). This kind of treatment also resulted in a significant preservation of valuable compounds (17.22 mg GAE 100 g−1) and antioxidant activity level (289.49 µM Trolox 100 g−1), reducing the wounding stress induced by processing operations for at least ten days.

Extending the Shelf-Life of Fresh-Cut Green Bean Pods by Ethanol, Ascorbic Acid, and Essential Oils

Green beans are a perishable crop, which deteriorate rapidly after harvest, particularly when minimally processed into ready-to-eat fresh-cut green beans. This study investigated the effectiveness of ethanol, ascorbic acid (AsA), tea tree essential oil (TTO), and peppermint essential oil (PMO) on the quality and storability of fresh-cut green bean pods samples stored at 5 °C for 15 days. Our results indicated that samples treated with ethanol, AsA, TTO, and PMO preserved appearance, firmness (except ethanol), chlorophyll content, and moisture compared with the samples without any treatment (control). Additionally, higher vitamin C, total soluble solids (TSS), total sugars, and total phenolic compounds (TPC) were observed in samples treated with ethanol, AsA, TTO, and PMO compared with the control. The most effective treatments for controlling microbial growth were ethanol followed by either TTO or PMO. All the treatments had positive effects on shelf life, maintained quality, and reducing microbial growth during 15 days of cold storage. A particular treatment can be selected based on the economic feasibility and critical control point in the value chain.

Shelf life extension of mozzarella cheese packed in preserving liquid with calcium lactate and bergamot juice concentrate

Traditional Mozzarella is a fresh cheese produced in Italian local market without additives that shows a short shelf life of about 5 d. This work tested the use of natural additives (bergamot juice concentrate-BJ and calcium lactate-CL) in preserving liquid for a Mozzarella cheese with the aim to extend its shelf life, regarding the microbial growth and overall cheese quality. Results of qualitative analyses showed that the preserving liquid with the mix of BJ and CL promoted an extension of mozzarella shelf life up to 20 d. A slightly reduced growth of Pseudomonas species was evidenced after 5 d of storage, whereas no inhibition of lactic acid bacteria was observed for the storage period. Moreover, mozzarella cheese packed in mixed preserving liquid possessed better textural properties, evidenced by the lowest proteolysis index measured after 13 d of storage, and a good antioxidant activity.

Effect of Chitosan/Nano-Titanium Dioxide/Thymol and Tween Films on Ready-to-Eat Cantaloupe Fruit Quality

The effect of chitosan/nano-titanium dioxide coating with antimicrobial agents on ready to eat cantaloupe fruit by chilling was investigated. In comparison with uncoated samples, ascorbic acid and juice leakage in chitosan/nano-titanium dioxide (CH/TiO2) treated fruit were significantly maintained. Likewise, the decrease of malondialdehyde (MDA) and total soluble solids (TSS) in chitosan/nano-titanium dioxide/thymol/tween (CH/TiO2/TT) coated fruits was also inhibited. Total mold and yeast population counts decreased from 2.60 to 1.60 log CFU/g, respectively. Moreover, activities of water (AW) and polyphenol oxidase (PPO) were also much lower than those in control sample fruit. The results indicated that (CH/TiO2/TT) coating was effective in enhancing the shelf life with acceptable in the internal and the external cantaloupe fruit quality.