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A study to verify whether the labeled sugar content in sugar-sweetened beverages (SSBs) corresponds to the actual sugar content in these products, thus enabling food monitoring studies to be conducted.

Onions (Allium cepa L.) are one of the most harvested fresh vegetables in the EU, with annual production of residues amounting to about 0.5 M tonnes. Onion skin is rich in flavonoids, especially quercetin, but this biomass is usually discarded during processing. These bioactive compounds could be useful for a protective nutrition or as a technical ingredient in food products. This research examined the stability and degradation of free quercetin, green solvents and procedures for the extraction of quercetin from onion peel, as well as stabilisation through liposomal encapsulation. Initial stability of quercetin was examined by UV-Vis spectrometry and antioxidant capacity determination (pH from 2 to 8, temperatures from 25 to 90 °C, exposure time up to 24 hours). At ambient conditions and pH 2 in the dark, the levels of quercetin were relatively well maintained in the initial hours of observation, and markedly depleted after 24 h. Higher pH values (> 7.4) and/or light at higher temperatures (> 60 °C) further accelerated the depletion profiles. Further metabolomic screening showed additional information regarding metabolite formation. Ethanol (70 %) extracts of onion peel were used in further examination and quercetin was monitored by HPLC-PDA. Either quercetin standard or onion peel extract were entrapped in liposomes, at different ratios between the standard/extract and liposomes (1:20 and 1:100). The greatest encapsulation efficienty was observed for quercetin standard prepared with liposomes in ratio 1:20 (roughly 90%), while encapsulation efficiency of quercetin from onion peel extract, was lower (roughly 75%) at the same conditions. The stability of encapsulated quercetin was followed for 30 days using HPLC- PDA. Over 80 % stabilisation of quercetin in yellow onion skin was achieved with liposomal preparation. Furthermoer, the interactions between quercetin and lipids were characterised by differential scanning calorimetry, indicating that quercetin interacted mainly with the polar headgroup regions of the liposomal bilayer. Onion peel thus presents a rich source of quercetin which could be employed in the formation of stable functional dosage forms. Liposomal encapsulation offers an approach to overcome quercetin degradation.

Due to the high lignocellulose content, as well as the high content of phenolic compounds, agro-industrial vegetable waste is well suited for valorization in packaging materials. As specialized packing materials, these materials may offer competitive advantages to paper producers, utilizing a low cost feedstock to produce a bespoke product of good quality. In our contribution, we focus on the production residues of various plant streams (e.g. growing and processing of onions, olives and pomegranates), to demonstrate how such diverse agro-industrial bio-waste materials could be fully exploited even before their reformulation. Onion skins and olive leaves both showed high antioxidant activity and the possibility to recover relatively high yields of bioactive compounds (roughly 100 mg of quercetin or oleuropein per g of dry extract). However, in pomegranate peel, the content of the antocyanins (roughly 0.3 mg of antocyanins per g of dry extract) was low. All three plant residues sources produced unique paper materials. Olive skins and olive leaves were used as two individual feedstocks, whereas the pomegranate peel was required to be added to cellulose. The resulting papers exhibited good technological properties, as well as interesting texture and appearance and might as such be suited for the production of special papers. The determined characteristics of the samples demonstrate a good potential for cascading use where paper production should be further studied following the extraction of bioactive components.

Jujube (Ziziphus jujuba Mill.) has favourable horticultural properties including adaptation to arid conditions, abiotic and biotic stresses, as well as positive impact on human health. The present study describes the characterization of genetic diversity of the germ­plasm of jujube from the Istrian peninsula, the determination of important chemical compounds, antioxidative properties in relation to antibacterial and antifungal activities of jujube fruit extracts, and the determination of nutritional properties of jujube fruit. The results of the genetic analysis showed that most of the samples from the Istrian peninsula belong to two recently introduced varieties, 'Li' and 'Lang', and the most widespread local variety 'Navadna žižola'. The local variety has smaller fruit than the ‘Li’ and ‘Lang’ varieties, with thick and fleshy mesocarp. Chemical analysis indicated that fruits of the local variety contained a valuable source of dietary fibre ((9.7±0.6) g/100 g) and were rich in minerals such as (in g/100 g dry mass): potassium (829±51), calcium (177±11) and phosphorus (129±19). Aqueous extracts showed slight antibacterial activity, while ethanol extracts had higher mass fractions of phenolic compounds (expressed as gallic acid equivalents (GAE), 5.8-8.7 mg/g) than the aqueous extracts, but did not show antimicrobial activity. Compounds other than phenolic compounds in jujube fruit may be more biologically active. Based on the results of these analyses, the local Istrian jujube variety is a promising candidate for cultivation potential.

Quercetin and typical flavonoids present in onion peel draw interest due to bioactive properties. They have numerous beneficial effects like anti obesity, antioxidant, anti- inflammatory and anticancer. The aim of this research was to extract quercetin from onion peel and to increase its bioavailability and stability by liposomal encapsulation. Liposomes are made of bilayers of amphiphilic molecules (such as phospholipids) which enable encapsulation both hydrophilic and lipophilic particles. For utilizing quercetin from onion peel, conventional solvent (70% ethanol)extraction was used and the amount of quercetin in this extract was determined by HPLC-PDA. Both quercetin standard and onion peel extract were encapsulated in liposomes, using different ratios between standard/extract and liposomes (1:20 and 1:100), in order to compare their encapsulation efficiency. The greatest encapsulation efficiency was observed for the quercetin standard prepared with liposomes in ratio 1:20 (87.06±1.13%), while encapsulation efficiency of quercetin from onion peel extract, was lower (75.81±2.12%) at the same conditions. The stability of encapsulated quercetin was followed for 30 days using HPLC- PDA. The interactions between quercetin and lipids were characterised by fluorescence polarisation measurements, electronic paramagnetic spectrometry and differential scanning calorimetry. Quercetin caused a small thermal destabilisation of DPPC transition which shows that the molecules interacted mainly with the polar headgroup regions of the bilayer. Onion peel presents a rich source of quercetin which could be employed in the formation of stable functional dosage forms.