Chemical composition and physicochemical properties of Phaeodactylum tricornutum microalgal residual biomass

2017 ◽  
Vol 23 (8) ◽  
pp. 681-689 ◽  
Author(s):  
LJ German-Báez ◽  
MA Valdez-Flores ◽  
JV Félix-Medina ◽  
CD Norzagaray-Valenzuela ◽  
DU Santos-Ballardo ◽  
...  

The production of photosynthetic biofuels using microalgae is a promising strategy to combat the use of non-renewable energy sources. The microalgae residual biomass is a waste by-product of biofuel production; however, it could prove to have utility in the development of sustainable nutraceuticals and functional foods. In this study, a comprehensive characterisation of the under-utilised Phaeodactylum tricornutum microalgae residual biomass is presented. Proximal composition, antioxidant capacity (using three different antioxidant assays; oxygen radical absorbance capacity; radical cation activity, ABTS; and radical scavenging activity, DPPH), and total phenolic content of free and bound polyphenols were determined. Additionally, the physicochemical properties of water activity, pH, water absorption index, water solubility index, and dispersibility were evaluated. Results revealed that P. tricornutum microalgae residual biomass exhibits a relatively high protein and carbohydrate content, with values of 36.67% and 46.78%, respectively; and most carbohydrates were found as total dietary fibre (45.57%), of which insoluble dietary fibre was the most predominant (43.54%). Antioxidant capacity values for total phytochemicals of 106.22, 67.93, 9.54 µM TE g−1 dw were determined by oxygen radical absorbance capacity, ABTS, and DPPH assays, respectively. Total phenolic content was found to be 2.90 mg GAE g−1 dw. Interestingly, antioxidant capacity and total phenolic content were higher in bound than in free phytochemical extracts. The physicochemical analysis showed P. tricornutum microalgae residual biomass to have suitable properties for the generation of a beverage with Aw, pH, water absorption index, water solubility index, and dispersibility values of 0.45, 7.12, 3.40 g gel g−1 dw, 2.5 g solids 100 g−1 dw, and 90%, respectively. Hence, P. tricornutum microalgae residual biomass could be considered a potential source of bioactive compounds suitable for the production of functional food exhibiting antioxidant capacity and high dietary fibre content.

HortScience ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 236-239 ◽  
Author(s):  
Brenner L. Freeman ◽  
Janet C. Stocks ◽  
Dennis L. Eggett ◽  
Tory L. Parker

Antioxidant phytochemical differences among cultivars and changes after storage have not been explored in primocane raspberries grown in a hot, dry climate. It was hypothesized that significant differences would be detected in total phenolics and antioxidant capacity [oxygen radical absorbance capacity (ORAC)] between cultivars and over time. ‘Autumn Bliss’ had the highest ORAC and phenolic content, whereas ‘Caroline’ had the lowest ORAC and phenolic content when fresh. Averaging all cultivars and pickings, refrigerated berries had a significantly higher total phenolic content than fresh or frozen berries, although some moisture loss occurred during standard refrigeration. Antioxidant capacity and total phenolic content of primocane raspberries grown in hot, dry conditions vary between cultivars, on average do not change significantly after storage, are higher later in the season, and are higher than supermarket cultivars.


2014 ◽  
Vol 23 (1) ◽  
pp. 38-47 ◽  
Author(s):  
Zhichun Xie ◽  
Jinshuan Fan ◽  
Denis Charlebois ◽  
Dominique Roussel ◽  
Claudine Dubé ◽  
...  

Eleven advanced strawberry lines (‘SJ011‑10’, ‘SJ0440‑2’, ‘SJ061‑8’, ‘SJ066‑3’, ‘SJ069‑3’, ‘SJ069‑12’, ‘SJ0814‑37’, ‘SJ8518‑11’, ‘K04‑12’, ‘LL0220‑10’ and ‘V151’) were evaluated for their yield, fruit quality, total phenolic content, total antioxidant capacity, and phenolic composition, and were compared with a commercial cultivar (‘Wendy’). The results showed that ‘SJ069‑3’ had excellent soluble solids content, mid-level titratable acidity, low weight loss, and the best firmness among all the cultivars. Higher total antioxidant capacity was found in ‘SJ069‑3’, according to ferric reducing antioxidant power and oxygen radical absorbance capacity assays, an indication that ‘SJ069‑3’ is a promising new cultivar for the fresh market. In addition to rich individual phenolics, ‘SJ061‑8’ had the highest total antioxidant capacity, which was significantly different from the other genotypes, suggesting the potential use of this line as parent material in breeding or as a functional food ingredient. There was a strong relationship between total antioxidant capacity and total phenolic content, according to Folin–Ciocalteu, ferric reducing antioxidant power, and oxygen radical absorbance capacity assays. This study confirms that anthocyanins are major phenolic compounds contributing to the main antioxidant power of strawberries.


2014 ◽  
Author(s):  
◽  
Anthony Olusegun Obilana

A pearl millet (Pennisetum glaucum) based instant beverage powder (PMIBP) was prepared from two different varieties of pearl millet (Agrigreen (AgG) and Babala (Ba)) by a combination of malting and extrusion cooking. The millet grains were germinated (30oC and 98% RH for 36 h), kilned (50oC for 48 h), cooled to room temperature, ground and stored in a chiller at 5oC until used. The raw and malted pearl millet grains were extruded under different parameters to accommodate the types of pre-treatment applied to the pearl millets. Combination processing of the pearl millet grain was achieved by extrusion of malted pearl millet of both varieties individually, and as a mixture of raw and malted pearl millet (50:50). The effect of the processing methods on the physical, functional, nutritional and biochemical properties of the raw and processed pearl millets varieties were evaluated. Combination processing led to a significant (p ≤ 0.05) decrease in total fat and total dietary fibre (TDF) (3.85 and 22.99 g/100 g, respectively) content of AgriGreen (AgG) extruded malted pearl millet (EMPM); a decrease in TDF (18.12 g/100 g) content of AgG extruded raw pearl millet-malted pearl millet mix (ERPMMPM). Combination processing led to a decrease in ash, total fat, total dietary fibre, Fe and Zn (1.76, 3.48, 14.26 g/100 g, 7.78 and 4.74 mg/100 g, respectively) content of Babala (Ba) EMPM. It also led to a significant (p ≤ 0.05) decrease in ash, total fat, TDF, Fe and Zn (1.88, 4.22, 21.71 g/100 g, 7.24 and 4.14 mg/100 g, respectively) content of Ba ERPMMPM. Regardless of the pearl millet variety, malting led to a significant (p ≤ 0.05) decrease in moisture, total, saturated, mono- and polyunsaturated fats, total dietary fibre iron, zinc and protein digestibility; a significant (p ≤ 0.05) increase in total carbohydrates, total phenolic content, antioxidant activity (TEAC) and water solubility index. Extrusion however, led to a significant (p ≤ 0.05) decrease in total dietary fibre, zinc, total phenolic content and protein digestibility; a significant (p ≤ 0.05) increase in ash, total, saturated and monounsaturated fats, total carbohydrates, iron, starch digestibility water absorption index (WAI) and water solubility index (WSI). The beverages of 10% total solids (8% pearl millet + 2% sugar for taste) prepared from the processed pearl millet were offered to an untrained consumer panel consisting of students and staff of the Cape Peninsula University of Technology, under similar sets of conditions in a sensory evaluation room at the Food Technology Department. The following characteristics of the products were rated and scored on a 9-point hedonic scale (1 – like extremely and 9 – dislike extremely): appearance, colour, aroma, flavour, mouth-feel and overall acceptability. In general, Ba RPM was rated 4 - like slightly, and AgG malted pearl millet (MPM) was rated 6 - dislike slightly and all other pearl millet samples from both varieties were rated 5 - neither like nor dislike.


2019 ◽  
pp. 49-59
Author(s):  
Nu Linh Giang Ton ◽  
Thi Hoai Nguyen ◽  
Quoc Hung Vo

Avocado peel has been considered as a potential source of natural antioxidants in which phenolics are among the most important compounds. Therefore, this study aims to optimize the extraction process of phenolics using response surface methodology and evaluate the corresponding antioxidant activity. From the quadratic model, the optimal condition was determined including the ethanol concentration 54.55% (v/v), the solvent/solute ratio 71.82/1 (mL/g), temperature 53.03 oC and extraction time 99.09 min. The total phenolic content and the total antioxidant capacity at this condition with minor modifications were 26,74 ± 0,04 (mg GAE/g DW) and 188.06 ± 1.41 (mg AAE/g DW), respectively. The significant correlation between total phenolic content and total antioxidant capacity was also confirmed. Key words: response surface methodology, central composite rotatable design, total phenolic content, total antioxidant capacity, avocado peel


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1255
Author(s):  
Sofia C. Lourenço ◽  
Débora A. Campos ◽  
Ricardo Gómez-García ◽  
Manuela Pintado ◽  
M. Conceição Oliveira ◽  
...  

Pineapple peel still contains an important amount of phenolic compounds and vitamins with valuable antioxidant activity. In this way, the aim of this study was the recovery of the bioactive compounds from pineapple peel using environmentally friendly and low-cost techniques, envisaging their application in food products. From the solid-liquid extraction conditions tested, the one delivering an extract with higher total phenolic content and antioxidant capacity was a single extraction step with a solvent-pineapple peel ratio of 1:1 (w/w) for 25 min at ambient temperature, using ethanol-water (80–20%) as a solvent. The resulting extract revealed a total phenolic content value of 11.10 ± 0.01 mg gallic acid equivalent (GAE)/g dry extract, antioxidant activity of 91.79 ± 1.98 µmol Trolox/g dry extract by the DPPH method, and 174.50 ± 9.98 µmol Trolox/g dry extract by the FRAP method. The antioxidant rich extract was subjected to stabilization by the spray drying process at 150 °C of inlet air temperature using maltodextrin (5% w/w) as an encapsulating agent. The results showed that the antioxidant capacity of the encapsulated compounds was maintained after encapsulation. The loaded microparticles obtained, which consist of a bioactive powder, present a great potential to be incorporated in food products or to produce bioactive packaging systems.


Foods ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 281 ◽  
Author(s):  
Saleha Akter ◽  
Michael E. Netzel ◽  
Ujang Tinggi ◽  
Simone A. Osborne ◽  
Mary T. Fletcher ◽  
...  

Terminalia ferdinandiana (Kakadu plum) is a native Australian plant containing phytochemicals with antioxidant capacity. In the search for alternatives to synthetic preservatives, antioxidants from plants and herbs are increasingly being investigated for the preservation of food. In this study, extracts were prepared from Terminalia ferdinandiana fruit, leaves, seedcoats, and bark using different solvents. Hydrolysable and condensed tannin contents in the extracts were determined, as well as antioxidant capacity, by measuring the total phenolic content (TPC) and free radical scavenging activity using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. Total phenolic content was higher in the fruits and barks with methanol extracts, containing the highest TPC, hydrolysable tannins, and DPPH-free radical scavenging capacity (12.2 ± 2.8 g/100 g dry weight (DW), 55 ± 2 mg/100 g DW, and 93% respectively). Saponins and condensed tannins were highest in bark extracts (7.0 ± 0.2 and 6.5 ± 0.7 g/100 g DW). The antimicrobial activity of extracts from fruit and leaves showed larger zones of inhibition, compared to seedcoats and barks, against the foodborne bacteria Listeria monocytogenes, Bacillus cereus, Methicillin resistant Staphylococcus aureus, and clinical isolates of Pseudomonas aeruginosa. The minimum inhibitory concentration and minimum bactericidal concentration in response to the different extracts ranged from 1.0 to 3.0 mg/mL. Scanning electron microscopy images of the treated bacteria showed morphological changes, leading to cell death. These results suggest that antioxidant rich extracts of Terminalia ferdinandiana fruits and leaves have potential applications as natural antimicrobials in food preservation.


2014 ◽  
Vol 12 (8) ◽  
pp. 858-867 ◽  
Author(s):  
Christina Zălaru ◽  
Claudia Crişan ◽  
Ioan Călinescu ◽  
Zenovia Moldovan ◽  
Isabela Ţârcomnicu ◽  
...  

AbstractThe aim of this research was to investigate the chemical composition of Coreopsis tinctoria Nutt. fruits extract, to highlight the potential of ultrasound assisted extraction in the fast preparation of extracts rich in polyphenols using different solvents (55%, 78% and 96% hydrous ethanol) and to evaluate the antioxidant potential of formulated extracts. LC-MS/MS was used to characterize the ethanolic extract from Coreopsis tinctoria Nutt. dried fruits. The extract contains different flavonoids (marein, flavanomarein, quercetagetin-7-O-glucoside, okanin aurone, leptosidin, luteolin, apigenin) and phenolic acids (chlorogenic acid, caffeic acid). Several parameters that could affect extraction efficiency were evaluated. Finally, this study focused on determination of plant extracts total phenolic content and their antioxidant capacity. The experimental results allowed the selection of the optimum operating parameters leading to the highest total polyphenolic content, expressed as gallic acid equivalents, and avoiding the degradation of phenolic compounds (ethanol 55%; extraction temperature 323.15 K, extraction time 30 min, liquid/solid ratio 20/1). A good relationship between total phenolic content and antioxidant capacity was obtained.


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