Microalgal biomass—a bio-based additive: evaluation of green smoothies during storage
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Date
2021-04
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International Food Research Journal
Abstract
Microalgae biomass addition to food has been studied for its nutritional fortification. The
present work investigates the impact of microalgae (Chlorella vulgaris and Dunaliella salina)
addition, in terms of quality characteristics, during a 28-day storage at 5°C. As much as 2.5%
(w/v) of C. vulgaris and D. salina were separately added to fresh green smoothies (spinach,
green apple, and cucumber) as food additive. Without any thermal application during storage
at 5°C, the changes in pH, total soluble, solid contents, titratable acidity, microbial loads,
phenolic contents, antioxidant activity, and sensory characteristics were determined. The
addition of microalgae biomass, either Chlorella or Dunaliella, was found statistically
significant, but this addition did not make a significant difference during the 28-day storage.
Compared to control samples (at day 0; 163.16 mg GAE/100 g and 2.56 mmol GAE/100 g),
Dunaliella biomass affected green smoothie more positively on total phenolic (at day 0;
395.79 mg GAE/100 g) and antioxidant activity (at day 0; 5.54 mmol GAE/100 g), than
Chlorella biomass (at day 0; 384.21 mg GAE/100 g and 4.22 mmol GAE/100 g). Also, a
shelf-life study on 28-day storage at 5°C found that Dunaliella-added smoothies were more
preferred by the panellists, while Chlorella-added samples exhibited off-odour and
off-flavour through storage. Smoothie supplementation with 2.5% microalgae biomass caused
a decrease in the initial microbial load. Due to this reduction, it can be said that microalgae
supplementation as an additive was effective, and microalgae-added samples were shown
below the "microbiologically consumable level" throughout the 28-day shelf-life study