Sensory evaluation and quality assessment of rosemary (Rosmarinus officinalis L.) during storage in a low-density polyethylene (LDPE) bags

The experiment aimed to analyse the changes of sensory quality for fresh-cut rosemary in a polyethylene LDPE bag with a ziplock closure (provides a convenient package opening and closing function). Samples of fresh-cut rosemary (20 ± 0.05 g) were packed in polyethylene LDPE bags (18 cm × 14 cm). Fresh-cut rosemary (20 ± 0.05 g) as control was put in polypropylene DuniForm PP boxes (14.5 × 20.5 × 3.5 cm) without film coating. The samples were stored in a cold room at +6 ± 0.5 °C for 14 days. On the first day, the quality parameters of samples were determined before packaging. During the storage, the measurements were provided on the 1st, 3rd, 5th, 7th, 10th, 12th and 14th days` of the experiment, in triplicate. During investigations, the gas composition in the free space of the package was provided with OXYBABY®V oxygen (O2) and carbon dioxide (CO2) analysing equipment as well as the weight loss (%) was determined in accordance with LVS ISO 1442:1997. The sensory quality of rosemary was evaluated according to methodology developed by Dr. sc. ing. Evita Straumīte. The colour of leaves was described using the RHS Colour Chart developed by the Royal Horticultural Society of UK (RHS). The obtained results were compared with the sensory analysis of fresh-cut rosemary during the storage without the use of packaging (control). The composition of the passive equilibrium shielding gas environment changed differently during the storage – as a result of respiration, the initial O2 content in the packaging environment decreased slowly from 19.1% (air) to 16.1% after 14 days of storage. The CO2 content of the packaging increased to 3.6% during storage. The weight loss during the storage for fresh-cut packaged rosemary during 14-day long storage was 0.99%. This parameter was significantly higher (p is less than 0.05; α = 0.05) for the control variant – the weight loss was 21.23% in DuniForm PP boxes without film coating during 12-day of storage. Based on the sensory evaluation, provided at the start of the experiment, both samples in the LDPE bags and the control were scored according to 5 points. The control variant was terminated on the 12th day of the research because of the firmness, juiciness and odour evaluated with 1.5, 1 and 1 point, respectively. For rosemary, stored in LDPE bags, on the14th day of experiment, colour was assessed with 4 points, firmness, juiciness and taste – with 3 points, but odour – with 2.5 points. The obtained results indicate that LDPE bags with ziplock closure are suitable for storage of fresh cut rosemary up to 14 days, preserving sensory properties.