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

Abstract

This work proposes for the first time a model for reusing almond (Prunus dulcis cv. Casteltermini from Sicily, Southern Italy) skin to formulate a new functional blackberry (Rubus ulmifolius Schott) jam. For this purpose, blackberries were analysed fresh and as jam, traditionally prepared with a minimum fruit amount of 80%. Different percentages of almond skin (20, 15, and 10% w/w) were added to jam. The phytochemical profile of enriched jam was investigated by LC-ESI/LTQOrbitrap/MS analyses. Anthocyanins, hydrolysable tannins, and triterpenoids were identified in a blackberry extract, while proanthocyanidins, flavonoids, and oxylipins were identified in an almond extract. The n-hexane extract of P. dulcis skin, investigated by GC–MS, evidenced linoleic, palmitic, and oleic acids as the main abundant compounds. Samples were investigated for their antioxidant activity using DPPH, ABTS, β-carotene, and FRAP tests. The hypoglycaemic and hypolipidemic effects were studied by α-amylase, α-glucosidase, and lipase inhibitory assays. In order to evaluate the effect of thermal process on enriched jam bioactivity, pasteurisation was applied. An increase in activities for all samples was observed, in particular for jam enriched with 20% w/w of almond skin. Based on obtained data, and supported by sensory analysis, we propose enriched jam as a promising source of compounds useful for preventing diseases associated with oxidative stress.

Chemical Compositions and Antioxidant Activities of Essential Oils, and Their Combinations, Obtained from Flavedo By-Product of Seven Cultivars of Sicilian Citrus aurantium L.

“…Citrus aurantium EOs and their mixes were screened for their radical scavenging activity by using 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) tests [ 42 ]. Briefly, a solution of ABTS radical was obtained by mixing 7 mM ABTS solution with 2.45 mM K 2 S 2 O 8 .…”

“…FRAP test is based on the reaction that involves 2,4,6-tripyridyl-s-triazine-Fe 3+ complex (TPTZ/Fe 3+ ). Briefly, a mixture namely FRAP reagent, consisting of 40 mM HCl, 20 mM FeCl 3 , and 0.3 M acetate buffer at pH 3.6, was prepared [ 42 ]. EO at concentration of 2.5 mg/mL in MeOH (100 μL) was mixed with FRAP reagent and water.…”

“…The capacity of the EOs and their combinations to inhibit lipid peroxidation in both initiation and propagation phase was studied by using the β-carotene bleaching test [ 42 ].…”

Reuse of Food Waste: The Chemical Composition and Health Properties of Pomelo (Citrus maxima) Cultivar Essential Oils

“…To assess the potential anti-obesity effects of pomelo EOs and their mixes, the activity of porcine pancreatic lipase (type II) (EC 3.1.1.3) activity was measured using p -nitrophenyl octanoate as a substrate [ 54 ]. The EOs were mixed with the enzyme solution (1 mg/mL in water), 0.005 M of p -nitrophenyl octanoate solution, and Tris-HCl buffer (pH = 8.5).…”

“…Both α-amylase and α-glucosidase are involved in carbohydrate digestion and have been recognised as targets for postprandial hyperglycaemia modulation [ 55 ]. For the α-amylase-inhibitory assay, a starch solution of α-amylase enzyme (EC 3.2.1.1) and colorimetric reagent were prepared [ 54 ]. Pomelo oils were added to the starch solution and left to react with the enzyme.…”