STORAGE STABILITY OF A MANGO, CARROT AND PUMPKIN BLENDED BEVERAGE CONSIDERED GOOD SOURCE OF β-CAROTENE

INTRODUCTION

The storage stability study of a beverage is highly important to know and understand the behavior of physicochemical, microbiological and sensory parameters. In a functional drink, the bioactive compound stability should be studied, since isomerization, oxidation, color fading and loss of healthy properties can occur by the processing technology. In this case, the stability of a fruit and vegetables blended beverage with bioactive compounds (carotenoids) was studied.

OBJECTIVES

To evaluate the storage behavior of a fruit and vegetables blended beverage and its bioactive compound (β-carotene) at different temperatures, through the analysis of microbiological and physicochemical parameters, as well as a sensory acceptance test.

METHODS

The product developed was formulated with 30% of pulp by weight (20% for mango, 8% for carrot and 2% for pumpkin) and Total Soluble Solids content (TSS) of 10.5°Brix. The beverage was subject to thermal pasteurization treatment at 80°C for two minutes, cooled and stored in 250mL bottles for 42 days at controlled temperature: 4°C, 20°C and 35°C. During this period some parameters were evaluated, such as color, pH, TSS (°Brix), titratable acidity (% of citric acid) and microbiological counts, as well as the carotenoids content by HPLC and UV-Vis spectrophotometry. These parameters were measured weekly, by randomly selecting two samples and making triplicate measurements.

After the storage period, a sensory acceptance test with 60 consumers was carried out for the samples stored at 20°C. A 7-point hedonic scale was used which contained extremes that indicated "very much disliked" to "liked very much". The data for temperature and storage time were processed by one-way ANOVA, followed by a multiple range test (Fisher's LSD).

RESULTS AND DISCUSSION

Significant differences were found among the samples on physicochemical properties due to temperature and storage time. The samples stored showed changes in CIELAB color space over time; a decrease in pH (< 0.1) and variations in TSS content (< 0.5 °Brix). Otherwise, titratable acidity (% of citric acid) increased during the storage time in the three temperatures (< 0.1%). The beverage presented microbiological quality.

The carotenoids content decreased with storage time and temperature. The carotenoids content (β-carotene) initially was 55,8 micrograms of Retinol Activity Equivalents (μg RAE) per 100 mL of sample by chromatography and 25,68 μg of β-carotene per sample gram by UV-Vis spectrophotometry. At 4°C, more than 90% of β-carotene content is retained with 55,0 μg RAE/100mL by chromatography and 23,7 μg/g by spectrophotometry. At 20°C, the β-carotene content decreases more rapidly, but more than 70% is preserved by chromatography with 41,7 μg RAE/100mL and more than 85% by spectrophotometry with 22,9 μg/g. Finally, at 35°C according to the chromatographic analysis only 49% of β-carotene content remained with 27,5 μg RAE/100mL, while by spectrophotometry more of 80% remained with 21,1 μg/g. The results by chromatography are more accurate and reliable, however the results by spectrophotometric method present a similar tendency for the time and temperature effect.

CONCLUSIONS

The beverage stability during storage was greater at 4°C than at 20°C and 35°C. This temperature allowed a better conservation of physicochemical properties and carotenoids content. At a sensory level, the drink was widely accepted.

According to the FDA Code of Federal Regulations, the beverage can be considered as antioxidant β-carotene high source for infants and children (3 years) due to more than 20% of the Reference Daily Intake (RDI) for vitamin A is present (300 μg RAE). There is a reduction in the carotenoids content after six weeks of storage at controlled temperature. Despite this reduction, at 4°C, the drink is still considered a good source (more of 10% of the RDI is present) for infants, children, adults and pregnant and lactating women; at 20°C it is not a good source for women in these states and at 35°C it is a good source only for infants and children (3 years). This could help to improve malnutrition situation and Vitamin A deficiency.

FINANCIAL SUPPORT

The authors thank the Universidad Nacional de Colombia Campus Bogotá, its Faculty of Engineering and Instituto de Ciencia y Tecnología de Alimentos – ICTA, as well as the project “Formulación y desarrollo de alimentos funcionales orientados a madres gestantes y lactantes y a población de la primera infancia” of the program “Investigación, desarrollo y transferencia tecnológica en el sector agropecuario y agroindustrial con el fin de mejorar las condiciones de productividad y competitividad de la economía rural de Bogotá y Cundinamarca”.