Quality evaluation and biological properties of Algerian commercial honeys labeled as Rosemary, Tamarisk, Thistle and multiflora

Mestrado de dupla diplomação com a Université Moulay TaherHoney is considered a natural sweet substance produced by honeybees, from the nectars of plant flowers and honeydews. Honey has always been regarded as a food that is beneficial for human health with several therapeutic qualities described. The quality of honey is still a top concern for experts as no good method has been defined so far for the simultaneous detection of different types of honey. Consequently, the development of easy, quick, precise analytical tools that may give data for assessing honey authenticity, is important. Because of that, it is essential to inform consumers of the mislabeling of honey with lower quality. This study aimed to evaluate the physicochemical characteristics and to assess the quality of Algerian honey from different botanical and geographical origins. For that, ten samples of honey with different marked botanical origins were analyzed, including three samples from rosemary honey, three from tamarisk honey, three from milk thistle honey and one multiflora honey. The quality of the samples was determined through different parameters. Melissopalynological and physicochemical analyses (color, moisture, pH, acidity, electrical conductivity, diastase index, proline, 5-hydroxymethylfurfural, mineral content, proteins, carbohydrates, energy, and ash) were performed, as well as the profile evaluation of sugar and phenolic compounds. Antioxidant activity (reducing power and DPPH free radical scavenging activity) antitumor and anti-inflammation activity were also evaluated. Finally, the presence of antibiotics, recurrent residues in honey, such as tetracyclines and sulphonamides were screened using the multi-analyte receptor assay system Charm II. The melissopalinological analysis showed the presence of 10 major types of pollen grains, with Rosmarinus officinalis, Cytisus stratitus and Centaurea sp. pollens as the most abundant. Furthermore, since no honeydew elements were detected, all the samples were classified as nectar honeys. Samples R1, R2, and R3 were classified as rosemary monofloral honey; samples T1, T2 and MF were classified as Cytisus striatus honey; CH1-CH3 were classified as Centaurea sp. and T3 as multifloral, which not always agreed with the labeled botanical origin. Generally, honey samples presented values of moisture, free acidity, 5-HMF, proline content, and diastase index within the limits of the legal requirements, suggesting that the honey was extracted at a correct ripeness stage. The results showed that almost all honey samples have light amber color, except the rosemary honeys which presented an extra white amber color. Although exhibiting a normal diastase index, the R2 and R3 samples presented a 5-HMF value higher than the admitted in the legislation, suggesting that less adequate heat treatments and/or conservation methods might have been employed. The most common minerals were potassium, sodium, calcium, manganese, while copper and Manganese were present in some samples in minor quantities and the heavy metals (cadmium and lead) are absent from all samples. The sugar profile, analyzed by high pressure liquid chromatography with refractive index detection (HPLC-RI), showed that fructose and glucose were the most abundant compounds, representing more than 60% of total sugars. Other sugars, such as turanose, maltulose and maltose were also detected in a lower proportion. Regarding the phenolic profile, nineteen compounds (eight phenolic acids and seven flavonoids), two isoprenoid compounds (trans, trans- and cis, trans- abscisic acid), one spermidine and one phenolic diterpene were identified. T2 sample showed a higher amount of phenolic acids than flavonoids. However, the most abundant compounds were the benzoic acid derivative which was detected in all samples. Concerning the evaluation of the antitumor activity and anti-inflammatory activity the samples showed a significant potential. Finally, concerning the antibiotics screening, not all the samples showed negative results.O mel é considerado uma substância doce natural produzida pelas abelhas, a partir dos néctares das flores das plantas e de meladas. O mel sempre foi considerado um alimento benéfico para a saúde, com várias qualidades terapêuticas descritas. A sua qualidade ainda é uma das principais preocupações para os especialistas, pois não há um método ideal para a classificação simultânea de diferentes tipos de mel. Consequentemente, é importante o desenvolvimento de ferramentas analíticas simples, rápidas e precisas que possam fornecer dados que permitam avaliar a autenticidade do mel. Por esse motivo, é essencial informar os consumidores da incorreta rotulagem de méis com baixa qualidade. O objetivo deste estudo foi avaliar as características físico-químicas e desse modo aferir a qualidade de méis argelinos com diferentes origens botânicas e geográficas. Para isso, foram recolhidas dez amostras de méis rotulados com diferentes origens botânicas, nomeadamente: três de mel de alecrim, três de mel de tamarino, três de mel de cardo e um de mel multifloral. A qualidade dos méis foi aferida através de diferentes parâmetros. Foram realizadas análises melissopalinológicas e físico-químicas (cor, humidade, pH, acidez, condutividade elétrica, índice diastático, prolina, 5-hidroximetilfurfural, conteúdo em minerais, proteínas, hidratos de carbono, energia e cinzas), bem como a avaliação do perfil em açúcares e compostos fenólicos. Também foi avaliada a atividade antioxidante (poder redutor e poder bloqueador de radicais livres) e atividade antitumoral e antiinflamatório. Finalmente, a presença de antibióticos, resíduos recorrentes no mel, como tetraciclinas e sulfonamidas, foram investigados através do sistema de despistagem Charm II. A análise melissopalinológica mostrou a presença de 10 tipos de grãos de pólen maioritários, sendo os pólenes de Rosmarinus officinalis, Cytisus stratitus e Centaurea sp. os mais abundantes. Além disso, e como não foram detetados elementos de melada, as amostras analisadas foram classificadas como méis de néctar: as amostras R1, R2 e R3 foram classificadas como mel monofloral de alecrim; as amostras T1, T2 e MF foram classificadas como mel de Cytisus striatus; CH1-CH3 foram classificados como de Centaurea sp. e T3 como multifloral, nem sempre coincidindo com a classificação utilizada no rótulo. De uma forma geral, as amostras de mel apresentaram valores de humidade, acidez livre, 5-HMF, teor de prolina e índice de diástase dentro dos limites requeridos legalmente, sugerindo que os méis foram extraídos no nível de maturação correto. Os resultados mostram que quase todas as amostras de mel apresentaram uma color âmbar clara, exceto o mel de alecrim que apresentou uma color âmbar extra clara. Apesar de apresentarem um índice de diástase normal, as amostras R2 e R3 apresentaram um valor de 5-HMF superior ao admitido na legislação, sugerindo a utilização de tratamentos térmicos e/ou métodos de conservação menos adequados. Os minerais mais comuns identificados foram o potássio, sódio, cálcio, enquanto cobre e manganês estiveram presentes em algumas amostras em quantidades menores e os metais pesados (cádmio e chumbo) estão ausentes em todas as amostras. O perfil dos açúcares, analisado por cromatografia líquida de alta pressão com deteção de índice de refração (HPLC-RI), mostrou que a frutose e a glucose foram os compostos mais abundantes, representando mais de 60% dos açúcares totais. Outros açúcares, como a turanose, a maltulose e a maltose, também foram detetados em menor proporção. Em relação ao perfil fenólico, foram identificados dezanove compostos (oito ácidos fenólicos e sete flavonóides), dois compostos isoprenóides (ácido trans, trans- e cis, trans-abscísico), uma espermidina e um diterpeno fenólico. No que diz respeito à avaliação da atividade antitumoral e atividade anti-inflamatória, as amostras apresentam potencial significativo. Finalmente, após o estudo de deteção de antibióticos verificou-se que nem todas as amostras estão isentas de resíduos

Discrimination of Quercus pyrenaica honeydew honey through the volatile profile

Honey is a natural product produced by Apis mellifera bees from the nectar of flowers, and called nectar honey, or secretions of plants or excretions produced by plant-sucking insects and called honeydew honey. The production of these honey can be observed in the north of the Iberian Peninsula, where forests of black oak (Quercus pyrenaica) exist, from the honeydew secretions produced in the plant, which result of the insect’s injuries or through phloem sap exudate in its acorns. The aim of this work is the discrimination of the black oak honeydew honey through its volatile profile. For that, forty-two samples, obtained in September of 2021, from four apiaries located in black oak forests within Montesinho Natural Park, Portugal, where characterized by the volatile profile. Also, acorn secretions were collected in Q. pyrenaica trees located near the apiaries. Volatiles were sampled by headspace solid phase microextraction (HS-SPME) and the chemical identification was performed by gas chromatography-mass spectrometry (GC-MS). A complex total ion chromatogram was obtained. The alcohols, aldehydes and terpenic derivatives were the most likely to relate the honeydew honey to its botanical origin, being 1-nonanol, α-terpineol, nonanal, hotrienol and phenylethyl alcohol the most abundant volatiles. Compounds such as 2,3-butanediol and cis-linalool oxide were presented and previously described in honeydew honey with forest origin. The above methodology was suitable for the isolation of low-molecular-weight aroma compounds that are important for authentication of Q. pyrenaica honeydew honey.info:eu-repo/semantics/publishedVersio

Production of chitosan-based biodegradable active films using bio-waste enriched with polyphenol propolis extract envisaging food packaging applications

Developing biodegradable active films has been a promising green approach to overcoming global concerns over the environmental pollution and human health caused by plastic utilization. This study aimed to develop active films based on chitosan (CS), produced from waste crayfish (Procambarus clarkii) shells enriched with bioactive extract (5–20%) of propolis (PS) and to characterize its properties, envisaging food packaging applications. The chromatographic profile of PS extract confirmed its richness, with 41 phenolic compounds. With increasing extract addition to the chitosan, the thickness of the films increased from 61.7 to 71.7 μm, causing a reduction in the light transmission rate, along with a greenish colour shift. The interactions between PS extract and CS was confirmed by infrared spectroscopy, at the same time that the microstructural integrity of the films was checked on the scanning electron microscopy micrographs. The findings also showed that addition of PS enhanced the films thermal stability and mechanical properties e.g., tensile modulus, yield strength, and stress at break. Besides, it improved the antioxidant and antimicrobial activities. Overall, CS-based composite films seem a promising green alternative to petroleum-based synthetic plastics allowing to extend the shelf life of food products due to their eco-friendly nature.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020) and contracts through the individual and institutional scientific employment program-contract with Soraia I. Falcão and Arantzazu Santamaria Echart. Thanks to the Programa Apícola Nacional 2020-2022 (National Beekeeping Program) for funding the project “Standardization of production procedures and quality parameters of bee products” and to Project PDR2020-1.0.1- FEADER-031734: “DivInA-Diversification and Innovation on Beekeeping Production”. Finally, this work is funded by the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project GreenHealth - Digital strategies in biological assets to improve well-being and promote green health, Norte-01-0145-FEDER-000042.info:eu-repo/semantics/publishedVersio