ARARUTA (Maranta arundinacea): NUTRITIONAL AND TECHNOLOGICAL VIABILITY OF THE RHIZOME
Biodiversity. Food preservation. Edible plants. Heat treatment. Shelf life.
Given the need to explore new food sources, discovering the nutritional potential of plants from biodiversity presents a promising alternative. Unconventional food plants (PANC) stand out as a way to meet food demand. Arrowroot, considered a PANC with high nutritional potential, has industrially relevant characteristics. Its edible part, the rhizome, rich in starch and fiber, has high technological potential. The time from planting to harvesting the rhizome varies between 10 and 12 months, considered long, making continuous commercialization unfeasible. Thus, post-harvest heat treatments increase the shelf life of this raw material, helping to revive its use as a minimally processed food. This research aimed to investigate the nutritional and technological potential of the arrowroot rhizome and was divided into two phases. In phase 1, a study was conducted on the effects of different blanching conditions on the raw material in the response variables of mass variation, enzymatic activity, color, and firmness. Scanning electron microscopy (SEM) and photographic documentation were also performed. In phase 2, the rhizome was characterized in its natural state and after bleaching, and its shelf life was determined through microbiological, physical, and chemical analyses, as well as photographic monitoring. A sensory analysis of the sample was performed, evaluating its acceptability by the tasters. The development of the first phase of the project allowed for the definition of the ideal rhizome bleaching condition through response surface analysis of variables with a significant effect (p < 0.05). This was considered to be a reduction in the activity of peroxidase and polyphenoloxidase enzymes, less alteration in rhizome firmness, lower values in total color difference (ΔE*), luminosity difference (ΔL*), and a Hue angle (hº) close to 90º. The SEM images helped in choosing the best combination, making it possible to observe which tests maintained the structural integrity of the plant tissue, preserving the starch granules after bleaching. Thus, the defined time-temperature combination was 4 minutes at 80ºC. In the nutritional characterization, the blanched sample showed a reduction in moisture content, a significant increase (p < 0.05) in lipid and carbohydrate content in the raw sample. Blanching caused darkening of the sample, evidenced by an increase in the browning index, a reduction in luminosity, and an increase in ΔE*. Firmness was not altered after blanching. During frozen storage, the samples presented satisfactory microbiological quality, being acceptable according to legal standards. The enzymatic activity of peroxidase and polyphenoloxidase remained reduced. pH and acidity fluctuated in both samples during storage, stabilising after 150 days. The raw sample lost 10% of its mass due to dehydration at the end of the storage period. Sensory analysis revealed a low acceptability index (< 70%), with texture being the most determining attribute in the tasters' preference, indicating that it was more fibrous than ideal. In the purchase intention analysis, most tasters rated it as "possibly would not buy". Thus, blanching and freezing appear to be effective alternatives for preserving the rhizome; however, it was not well accepted for consumption as a minimally processed food. The rhizome shows greater potential for use as a raw material for the production of starches and flours.