The Valorisation of Melissa officinalis Distillation By-Products for the Production of Polyphenol-Rich Formulations.

Lemon balm (Melissa officinalis) is an aromatic and medicinal plant, rich in bioactive ingredients and with superior antioxidant activity. The essential oil of this plant is an expensive product, so the use of the by-products of the essential oil industry is particularly useful. The aim of this research was to process Melissa officinalis distillation by-products to develop a series of polyphenol-rich formulations. In the present research, lemon balm was distilled in a laboratory-scale distiller, and the recovered by-product was used for further successive extractions with acetone and water, using a fixed-bed semi-batch extractor. Acetone extract exhibited relatively poor results as far as yield, phenolic composition and antiradical activity are concerned. However, the aqueous extract presented high yield in both total phenolic content (i.e., 111 mg gallic acid equivalents (GAE)/g, on a dry herb basis (dw)), and anti-radical capacity (205 mg trolox equivalents (TE)/g dw). On a dried extract basis, the results were also impressive, with total phenols reaching 322 mg GAE/g dry extract and antiradical capacity at 593 mg TE/g dry extract. The phenolic components of the extract were identified and quantified by HPLC-DAD. Rosmarinic acid was the major component and amounted to 73.5 mg/g dry extract, while the total identified compounds were quantified at 165.9 mg/g dry extract. Finally, formulations with two different wall materials (gum arabic-maltodextrin and maltodextrin) and two different drying methods (spray-drying and freeze-drying) were applied and evaluated to assess their performance, yield, efficiency and shelf-life of total phenolic content and rosmarinic acid concentration. From the present investigation, it is concluded that after one year of storage, rosmarinic acid does not decrease significantly, while total phenolic content shows a similar decrease for all powders. According to the yield and efficiency of microencapsulation, maltodextrin alone was chosen as the wall material and freeze-drying as the preferred drying method.

Kinetics of Carotenoids Degradation during the Storage of Encapsulated Carrot Waste Extracts.

The encapsulates of carrot waste oil extract improved the antioxidant properties of durum wheat pasta. The aim of this research was to study the kinetics of carotenoids degradation in the freeze-dried (FDE) and spray-dried (SDE) encapsulates of carrot waste extract during storage at four different temperatures (+4, +21.3, +30, +37 °C) up to 413 days by HPLC. Carotenoids levels decreased as a function of time and temperature, following zero-order kinetics. At 4 °C carotenes were stable for at least 413 days, but their half-lives decreased with increasing temperatures: 8-12 months at 21 °C; 3-4 months at 30 °C; and 1.5-2 months at 37 °C. The freeze-drying technique was more effective against carotenes degradation. An initial lag-time with no or very limited carotenes degradation was observed: from one week at 37 °C up to 3 months (SDE) or more (FDE) at 21 °C. The activation energies (Ea) varied between 66.6 and 79.5 kJ/mol, and Ea values tended to be higher in FDE than in SDE.

Aronia Melanocarpa: Identification and Exploitation of Its Phenolic Components.

The phenolic components of Aronia melanocarpa were quantitatively recovered by three successive extractions with methanol. They comprise anthocyanins (mainly cyanidin glycosides) phenolic acids (chlorogenic and neochlorogenic acids) and flavonols (quercetin glycosides). Approximately 30% of the total phenolic compounds are located in the peel and the rest in the flesh and seeds. Peels contain the major part of anthocyanins (73%), while the flesh contains the major part of phenolic acids (78%). Aronia juice, rich in polyphenols, was obtained by mashing and centrifugation, while the pomace residue was dried and subjected to acidified water extraction in a fixed bed column for the recovery of residual phenolics. A yield of 22.5 mg gallic acid equivalents/g dry pomace was obtained; however, drying caused anthocyanins losses. Thus, their recovery could be increased by applying extraction on the wet pomace. The extract was encapsulated in maltodextrin and gum arabic by spray drying, with a high (>88%) encapsulation yield and efficiency for both total phenols and anthocyanins. Overall, fresh aronia fruits are a good source for the production of polyphenol-rich juice, while the residual pomace can be exploited, through water extraction and spray drying encapsulation for the production of a powder containing anthocyanins that can be used as a food or cosmetics additive.

Spray-drying encapsulation of microwave-assisted extracted polyphenols from Moringa oleifera: Influence of tragacanth, locust bean, and carboxymethyl-cellulose formulations.

In this work, polyphenols from Moringa oleifera (Mor) leaves were extracted by microwave-assisted extraction (MAE) and encapsulated by spray-drying (SD). Particularly, we explored the influence of tragacanth gum (TG), locust bean gum (LBG), and carboxymethyl-cellulose (CMC) as wall-materials on the physicochemical behavior of encapsulated Mor. Single or combined wall-material treatments (100:00 and 50:50 ratios, and total solid content 1%) were tested. The results showed the wall-material had a significant effect on the process yield (55.7-68.3%), encapsulation efficiency (24.28-35.74%), color (yellow or pale-yellow), total phenolic content (25.17-27.49 mg GAE g-1 of particles), total flavonoid content (23.20-26.87 mg QE g-1 of particles), antioxidant activity (DPPH• = 5.96-6.95 mg GAE g-1; ABTS•+ = 5.61-6.18 mg TE g-1 of particles), and particle size distribution (D50 = 112-1946 nm) of the encapsulated Mor. On the other hand, SEM analysis showed smooth and spherical particles, while TGA and DSC analyses confirmed the encapsulation of bioactive compounds based on the changes in thermal peaks. Finally, XRD analysis showed that the particles have an amorphous behavior. The encapsulated Mor produced with individual TG or CMC demonstrated better properties than those obtained from mixed gums. Thus, TG or CMC might be feasible wall materials for manufacturing encapsulated Mor that conserve the phenolic content and antioxidant activity.