Recycling of Almond By-Products for Intestinal Inflammation: Improvement of Physical-Chemical, Technological and Biological Characteristics of a Dried Almond Skins Extract

Abstract

Background: Almond skins are rich in bioactive compounds that undergo oxidation/degradation phenomena and are poorly soluble in water, reducing in vivo absorption and bioavailability, factors that influence the pharmacological activity of an active product. We developed a dried acetonic almond skins extract/cyclodextrin complex to improve extract solubility, dissolution rate and biological activity. Methods: A lyophilized acetonic almond skin extract was produced. To optimize complex formulation, phase solubility studies and complex characterization (absorption studies, differential scanning calorimetry (DSC), morphology, solubility studies) were performed. To evaluate a possible use in healthy products, tumor necrosis factor-α levels and reactive oxygen species release, as well as cicloxygenase-2 and inducible nitric oxide synthase expression in intestinal epithelial cells, were also evaluated. Results: Phase solubility studies showed a Bs-type profile. A 1:1 dried acetonic almond skins extract/cyclodextrin ratio was able to improve extract water solubility and dissolution rate (100% in 45 min). The UV-Vis spectra of complex revealed a hypsochromic and hyperchromic effect, probably due to a partial inclusion of extract in cyclodextrin cavity through weak bonds, confirmed by DSC and morphology studies. The technological improvement in the extract characteristics also led to better biological activity. In fact, the complex effectively reduces tumor necrosis factor-α levels with respect to the pure extract and significantly inhibits the reactive oxygen species release, even if only at the lower concentration of 5 μg/mL. Conclusion: The complex was able to overcome solubility problems and could be used in inflammatory disease.

Almond By-Products: Valorization for Sustainability and Competitiveness of the Industry

“…Furthermore, the same extracts promoted the reduction of pro-inflammatory CKs levels, mostly intereleukin-1β (IL-1β) and IL-6, as well as the mediator nitric oxide (NO) levels. Such effects were in accordance with those observed for pepsin hydrolysates obtained from almond flour [67] and those provided by acetonic dried almond skin extracts from the Corrente/Tuono mixture variety on LPSinduced intestinal IEC-6 cell line, together with the inhibition of oxidative stress, via ROS levels reduction [68].…”

Eudraguard® Natural and Protect: New “Food Grade” Matrices for the Delivery of an Extract from Sorbus domestica L. Leaves Active on the α-Glucosidase Enzyme

“…The SOE sd spectra showed characteristic peaks (-OH stretching at 3275.12 cm −1 ; C-H stretching at 2932.78 cm −1 ; aromatic fingerprinting from 1868.80 cm −1 to 1829.82 cm −1 ; C=O stretching vibrations from 1772.02 cm −1 to 1670.02 cm −1 ; C=C stretching vibrations from 1636.06 cm −1 to 1507.76 cm −1 ; 1488.99 cm −1 –1472.63 cm −1 symmetric -CH 2 bending vibrations; asymmetric -CH 3 bending vibrations from 1456.95 cm −1 to 1418.70 cm −1 ; symmetric -CH3 bending vibrations from 1339.54 cm −1 to 1362.63 cm −1 ; C-C stretching from the phenyl group from 1300 cm −1 to 1450 cm −1 ; C-O stretching from 1244.07 cm −1 to 1075.17 cm −1 ) with signals ascribable to flavonoids. The region between 4000.0 cm −1 and 3000.0 cm −1 was identified as a flavonoid hydroxyl group signal; the regions at 1670.0 cm −1 and 1620.0 cm −1 were polyphenol saturation and conjugation bond signals, respectively; and 1650 cm −1 and 1600 cm −1 were identified as the characteristic aromatic signals of flavonoids [ 33 , 34 ]. Furthermore, SOE DSC showed a series of signals (from 230 °C to 270 °C) that were close together, probably ascribable to the blend of molecules belonging to the same class of polyphenols.…”

Almond (Prunus dulcis cv. Casteltermini) Skin Confectionery By-Products: New Opportunity for the Development of a Functional Blackberry (Rubus ulmifolius Schott) Jam

“…A statistically significant decrease in sweetness and mouthfeel notes was observed in all enriched jams, in comparison with the control jam. Despite Lauro et al [ 25 ] reported that almond skins possess “woody” and “earthy” organoleptic characteristics that can reduce the consumer’s preferences. In our case, we have not encountered this problem, since these sensory attributes are probably masked by the flavour and taste of the jam.…”

“…Moreover, clinical studies have demonstrated that a regular almond consumption can reduce the risk of several diseases in humans [ 24 ]. In part, this bioactivity can be ascribed to the phytochemicals present in the skin, particularly to the polyphenols with proven antioxidant and health-promoting activity [ 18 , 21 , 25 ].…”