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Impacto do processamento sobre as características físico-químicas, reológicas e funcionais de frutos da gabirobeira (Campomanesia xanthocarpa Berg)
| Content Provider | Semantic Scholar |
|---|---|
| Author | Santos, Marli Da Silva |
| Copyright Year | 2011 |
| Abstract | The gabirobeira (Campomanesia xanthocarpa Berg) is a fruit-bearing tree belonging to the family Myrtaceae native to Brazil. The aim of this study was to evaluate the technological potential of the gabiroba fruit, through juice extraction, production of frozen pulp, extraction of pectin from the pulp and oil from the seeds. The fruits were collected in populations of native plants in five communities in the district of Itaiacoca, near the city of Ponta Grossa (PR). An average of three kilograms of fruit per plant were manually harvested from the trees at random positions and orientations, in three different maturation stages, adopting the criterion of predominant color of the skin. The three stages of maturity were characterized as: green (VF), partially mature starting pigmentation (FIP), or mature, considered suitable for consumption, with predominant yellow to orange color (FAL). The physicochemical properties of the fruits were evaluated under these three stages of maturation for the following parameters: pH, total soluble solids (SS), total acidity (TA), chroma a*, b*, L*; Hue angle (h), SS/TA ratio, total sugars and pulp yield (%). Multivariate statistical analysis was performed. It was observed that, although collected from naturally dispersed native plants, the fruits showed well defined characteristics in relation to the maturation stage in which they were collected. Cluster analysis showed the formation of a large group divided into subgroups that showed some degree of similarity based on a set of traits. The results allowed the inference of certain variability between samples collected in different regions. The pulp was obtained from ripe fruit which were selected, classified, sanitized, grinded, centrifuged, packed in sealed polyethylene bags and frozen (-20 ± 2 ° C ) for up to 180 days. The pulp samples were evaluated monthly regarding the levels of bioactive compounds including: vitamin C, flavonoids and phenolic compounds, determined by spectrophotometer UV/VIS and carotenoids determined by HPLC (high performance liquid chromatography). To determine the concentrations of calcium, iron, manganese, zinc and copper, atomic absorption spectrophotometry was utilized. A flame photometer was used for the determination of sodium and potassium. The phosphorus content was measured through VIS spectrophotometry. The DPPH and ABTS methods were employed to evaluate the antioxidant potential. Rheometry was performed trough HAAKE rheometer RS Rheoestress coupled with a Peltier temperature controller (TC81) with water term circulator DC5B3 sensor using plateplate PP-35ti. The gabiroba pulp showed appreciable amounts of minerals: iron, phosphorus, calcium, potassium, zinc and manganese, and total phenolic compounds (131.90 mg 100g gallic acid), vitamin C (313.21 mg 100g ascorbic acid) and carotenoids (290.84 μg.g-1), 42% of which composed of beta-carotene, the main precursor of vitamin A (20.61 μg.g-1 retinol equivalent (RE). Throughout the storage of the pulp, there was a reduction of approximately 10% in the levels of phenolic compounds, 5.35% of flavonoids and 23.52% of vitamin C. The gabiroba pulp showed pseudoplastic behavior with yield stress. The mechanical spectrum of gabiroba pulp showed that the storage modulus (G ') and loss (G ") were independent of frequency across the range studied. The polysaccharides were extracted from the pulp of ripe fruit in different conditions and extracting agent: (a) distilled water (26°C); (b) citric acid with differ ent concentrations and temperature (0.5% and 5%/50°C and 100°C); and (c) NaOH 2 mol L1 (26±2°C). Each fraction of polysaccharides was evaluated for yield, protein content, total sugar and uronic acid content trough UV/VIS spectrophotometric techniques. Monosaccharide composition was determined by gas-liquid chromatography. The degree of esterification was determined by infrared spectroscopy. Rheological properties were determined using a cone-plate sensor C-60 2Ti. It was observed that the yield is proportional to the extraction conditions: time, temperature and extracting agent. Polysaccharide fractions isolated from the pulp consisted mainly of uronic acid, arabinose, rhamnose and galactose in different proportions. The extraction conditions interfered with monosaccharide composition, degree of esterification and gelling power of the polysaccharides. At the concentration of 30g.L, the pectin showed pseudoplastic behavior. All fractions of isolated pectins formed gels. All fractions of polysaccharides extracted from gabiroba, even those obtained under more drastic conditions, showed characteristic resistance to variations in temperature. The oil obtained from seeds of the gabiroba fruits showed significant levels of bioactive compounds and the results of fatty acid contents indicated a high degree of unsaturation. A product rich in oleic and linoleic acids was obtained after extraction with solvent. The juice was obtained through enzymatic treatment of the pulp. The juice was extracted by 2 factorial design varying the enzyme concentration and time, setting the temperature of incubation at 50 °C. The juice extracted enzymatica lly presented good retention of bioactive compounds and considerable antioxidant potential. The juice also showed a good acceptability. The use of enzymes in order to increase extraction of juice was effective in gabiroba. The fruits were adequate for making jam in both conventional and reduced calorie formulations. The jam had a considerable nutritional value as high levels of vitamin C, phenolic compounds, carotenoids and antioxidant activity were retained. Both jam and juice made from gabiroba had good acceptability and are therefore good alternatives to encourage the consumption adding value to the fruit. Key-words: gabiroba, Campomanesia xanthocarpa, processing, bioactive compounds, frozen pulp, juice extraction, jam preparation. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://acervodigital.ufpr.br/bitstream/handle/1884/25696/Tese%20Marli%20da%20Silva%20Santos%20-%20Tecnologia%20em%20Alimentos.pdf?isAllowed=y&sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
