Chemical and Bioactive Screening of Green Polyphenol-Rich Extracts from Chestnut By-Products: An Approach to Guide the Sustainable Production of High-Added Value Ingredients.

Opportunities for the valorisation of agro-industrial residues of the chestnut (Castanea sativa Mill.) production chain have been fostered with the production of multifunctional polyphenol-rich extracts with the potential to be introduced as natural additives or active components in several products. Nonetheless, it is crucial to explore the feasibility of different extracts from the various by-products for these applications through the exhaustive study of their composition and bioactivities without losing sight of the sustainable character of the process. This work aimed at the screening of the phenolic compound composition and bioactivities of different green extracts of chestnut burs, shells and leaves, as the first step to establish their potential application as natural ingredients, primarily as food preservatives. To this end, maceration (MAC) as a conventional extraction method besides ultrasound and microwave-assisted extractions (UAE and MAE) was employed to obtain the extracts from chestnut by-products using water (W) and hydroethanolic solution (HE) as solvents. Phenolic compounds were analysed by HPLC-DAD-(ESI-)MS/MS; the antioxidant capacity was assessed by colourimetric assays, and the antimicrobial activity was evaluated against several strains of food-borne bacteria and fungi. The leaf extracts obtained by MAC-HE and UAE-HE presented the highest concentration of phenolic compounds (70.92 ± 2.72 and 53.97 ± 2.41 mg.g-1 extract dw, respectively), whereas, for burs and shells, the highest recovery of total phenolic compounds was achieved by using UAE-HE and UAE-W (36.87 ± 1.09 and 23.03 ± 0.26 mg.g-1 extract dw, respectively). Bis-HHDP-glucose isomers, chestanin and gallic acid were among the most abundant compounds. Bur extracts (MAC-HE and UAE-HE) generally presented the highest antioxidant capacity as measured by TBARS, while the best results in DPPH and reducing power assays were found for shell extracts (MAE-W and MAC-HE). Promising antibacterial activity was noticed for the aqueous extracts of burs, leaves and hydroethanolic extracts of shells, with emphasis on the MAE-W extract of burs that showed bactericidal activity against E. cloacae, P. aeruginosa and S. aureus (MBC 5 mg.mL-1). Overall, it can be concluded that chestnut by-products, including burs, shells and leaves, are sources of polyphenolic compounds with significant antioxidant and antimicrobial activities. The choice of extraction method and solvent greatly influenced the composition and bioactivity of the extracts. These findings highlight the potential of chestnut by-products for the development of natural additives, particularly for food preservation, while also emphasizing the importance of sustainable utilization of agricultural waste materials. Further research is warranted to optimize extraction techniques and explore additional applications for these valuable bioactive compounds.

Trust your gut: Bioavailability and bioaccessibility of dietary compounds.

Studying the composition of a certain food is not enough to predict its health benefits. Research over the past decades has decisively strengthened the notion that any putative health benefit is best related to the fraction of compounds transferred from ingested foods into the body since the absorption may be incomplete after oral consumption. In other words, the bioavailability of food components is crucial information. Therefore, a variety of in vitro models have been developed to predict their bioaccessibility and bioavailability in the most diverse food matrices and food products. These models can also be applied to study the impact of several endogenous or exogenous factors on the bioaccessibility and bioavailability of nutrients and bioactive compounds, guiding nutrition and food scientists, technologists, and engineers towards the development of strategies to optimize the positive impact of the diet on well-being and quality of life. While bioavailability is ideally examined in human volunteers, in vitro digestion methods, as well as intestinal absorption and microphysiological models, simulate human physiological conditions. Additionally, in vitro methods are alternatives to offset ethical, economical, and experimental limitations associated with in vivo studies conducted either with individuals or animals. This graphical review draws parallels between in vitro models mimicking digestion processes, uptake, absorption, metabolism, and distribution of dietary compounds and human physiology.

Comparison of two rapid descriptive sensory techniques for profiling and screening of drivers of liking of sorghum breads.

Rapid descriptive methods have emerged as a relatively simple alternative for screening the sensory attributes of products that drive their liking, and may contribute to identify sorghum genotypes with potential for development of gluten-free breads with higher consumer acceptance. Two rapid techniques, Check-All-That-Apply (CATA) and Optimized Descriptive Profile (ODP), were herein compared on their ability to describe, discriminate and identify the drivers of liking of sorghum breads. Gluten-free bread formulations were developed using flours from selected sorghum genotypes (CMSS005, BR 501, BRS 332, BRS 330, BRS 305 and 1167048), besides commercial sorghum and rice flours. A semi-trained panel (n = 18) evaluated the samples using the ODP method, whereas consumers (n = 124) completed the CATA questionnaire and rated the liking in a 9-point hedonic scale. A total of 24 and 11 sensory descriptors were perceived by assessors as different among samples for CATA and ODP, respectively, with color and appearance-related attributes critical to discriminate samples in CATA, whereas flavor and texture descriptors had also prominent contribution in ODP. A similar pattern of sample distribution was noticed for both methods, which were shown to be highly and positively correlated (RV = 0.92, p < 0.002). Genotypes influenced the consumer perception of sorghum breads, being the BRS 332 and the CMSS005 breads among the most and the least accepted samples for either consumer segment, respectively. While 10 drivers of liking were identified by CATA, including 'appearance of whole flour breads', 'uniform alveoli', 'neutral flavor' and 'soft aroma', in ODP 'crumb color', 'crust color', 'spots' and 'traditional bread aroma' drove bread acceptance. In summary, both methods were successfully applied and provided similar pattern of sample discrimination, whereas the attributes used for sample characterization, as well as those identified as drivers of liking were generally different. The ODP offers a simpler option for a quantitative perspective, while CATA remains as an easy method considering qualitative aspects, being clearly faster than ODP.

Marigold carotenoids: Much more than lutein esters.

Carotenoids constitute a large group of lipophilic pigments whose health-promoting benefits have been widely recognized. Hydroxy-containing carotenoids can be found in both free form or esterified with fatty acids in several plant matrices, but the native carotenoid profile is overall poorly explored due to the difficulty of analyzing carotenoid esters. One of the main natural sources of carotenoids is the marigold flower, which has been extensively used by the industry for the production of food colorants or supplements, both often manufactured with no saponification process. Although lutein esters are well established as the major compounds naturally found in marigold petals and their products, carotenoid esters other than the lutein ones have not been extensively examined. We carried out a comprehensive identification of carotenoids and carotenoid esters from marigold petals by LC-DAD-(APCI+)MS/MS. Whereas 18 carotenoids were identified in the saponified extract, 56 were identified when no saponification procedure was carried out: 6 free carotenoids, 20 monoesters and 30 diesters. This is the first time that esters of zeaxanthin, violaxanthin, auroxanthin, zeinoxanthin and ß-cryptoxanthin are identified in marigold. The structural information obtained through characteristic fragmentation patterns and diagnostic fragments in MS and MS/MS spectra (APCI+) sustained the differentiation between carotenoid esters with similar characteristics. Therefore, the separation of carotenoids by reversed-phase liquid chromatography using C30 columns in combination with DAD and APCI-MS/MS detection allowed high sensitivity and selectivity for carotenoid ester analysis.

An in vitro digestion method adapted for carotenoids and carotenoid esters: moving forward towards standardization.

In vitro digestion methods are a useful approach to predict the bioaccessibility of food components and overcome some limitations or disadvantages associated with in vivo methodologies. Recently, the INFOGEST network published a static method of in vitro digestion with a proposal for assay standardization. The INFOGEST method is not specific for any food component; therefore, we aimed to adapt this method to assess the in vitro bioaccessibility of carotenoids and carotenoid esters in a model fruit (Byrsonima crassifolia). Two additional steps were coupled to the in vitro digestion procedure, centrifugation at 20 000g for the separation of the aqueous phase containing mixed micelles and exhaustive carotenoid extraction with an organic solvent. The effect of electrolytes, enzymes and bile acids on carotenoid micellarization and stability was also tested. The results were compared with those found with a simpler method that has already been used for carotenoid bioaccessibility analysis. These values were in the expected range for free carotenoids (5-29%), monoesters (9-26%) and diesters (4-28%). In general, the in vitro bioaccessibility of carotenoids assessed by the adapted INFOGEST method was significantly higher (p < 0.05) than those assessed by the simplest protocol, with or without the addition of simulated fluids. Although no trend was observed, differences in bioaccessibility values depended on the carotenoid form (free, monoester or diester), isomerization (Z/E) and the in vitro digestion protocol. To the best of our knowledge, it was the first time that a systematic identification of carotenoid esters by HPLC-DAD-MS/MS after in vitro digestion using the INFOGEST protocol was carried out.

Two-step cleanup procedure for the identification of carotenoid esters by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

Carotenoids are naturally found in both free form and esterified with fatty acids in most fruits; however, up to now the great majority of studies only evaluated their composition after saponification. This fact is easily explained by the difficult to analyze carotenoid esters. Preliminary studies showed that cleanup procedures in the extract are necessary for further analysis by LC-MS/MS since triacylglycerols (TAGs) impair the MS detection. Considering these facts, we developed a new cleanup procedure to remove TAGs and other lipids from carotenoid fruit extracts. This procedure is based on physical removal of solid lipids at low temperature followed by open column chromatography on MgO and diatomaceous earth. Before cleanup, four carotenoid diesters and two free xanthophylls were identified in murici (Byrsonyma crassifolia), corresponding to about 65% of the total chromatogram area. After carrying out the two-step cleanup procedure, 35 carotenoids were identified, being 14 monoesters, six free carotenoids and 15 carotenoid diesters. We can conclude that this two-step procedure was successfully applied to murici, an Amazonian fruit, which contains high amounts of lipids.

Caracterização físico-química de variedades de amora-preta da região sul do Brasil / Physicochemical characterization of blackberry from the Southern Region of Brazil

A amora-preta (Rubus sp.) é uma fruta cuja exploração comercial está iniciando no Brasil. Seu cultivo iniciou na década de 70 e vem aumentando com a introdução e adaptação de novas cultivares. Porém, pouco se conhece sobre as disparidades geradas na composição e nas características das frutas dessas novas plantas. O objetivo deste trabalho foi avaliar as características físico-químicas de diferentes cultivares ('Tupy', 'Guarani' e 'Cherokee') e seleções (02/96, 07/001 e 03/001) de amora, que estão sendo estudadas para originar cultivares adaptadas à região Sul do Brasil. Foram analisados a cor objetiva, sólidos solúveis (SS), pH, acidez titulável, composição centesimal e ácidos graxos de amoras. As frutas apresentaram umidade entre 84,8 e 90,3%; proteína entre 0,09 e 0,14%, fibra alimentar entre 5,8 e 5,5% e cinzas entre 0,27 e 0,49%. A seleção 02/96 apresentou menor teor de cinzas. Os SS variaram entre 7,3 a 10,2°Brix, a acidez titulável variou entre 1,30 e 1,58% em ácido cítrico e o pH entre 2,8 e 3,1. A seleção 03/001 apresentou menor valor de SS que as demais e menor tendência ao vermelho, mas maior intensidade de cor que a cultivar 'Tupy'. Os ácidos graxos encontrados em maior concentração foram o ácido palmítico (22-29%), oléico (13-32%) e linoléico (15-33%), com diferenças nas concentrações entre os tipos de amora. As variedades de amora-preta avaliadas apresentaram bom valor nutricional com níveis de açúcar e acidez adequados para a industrialização, além de conter ácidos graxos importantes para a manutenção da saúde.

Blackberry (Rubus sp.) is a fruit whose commercial exploitation is starting in Brazil. Its cultivation began in the 70's and is increasing with the introduction and adaptation of new cultivars. However, little is known about the disparities in the composition and characteristics of the fruit from these new plants. The objective of this study was to evaluate the physicochemical characteristics of different cultivars ('Tupy', 'Guarani' and 'Cherokee') and selections (02/96, 07/001 and 03/001) of blackberries, which are being studied to generate cultivars adapted to Southern Region of Brazil. The objective color, soluble solids (SS), pH, titratable acidity, proximate composition and fatty acids of blackberries were evaluated. The fruit humidity ranged between 84.8 and 90.3%; protein between 0.09 and 0.14%, dietary fiber between 5.5 and 5.8% and ash between 0.27 and 0.49%. Selection 02/96 had the lowest ash content. SS ranged from 7.3 to 10.2°Brix, titratable acidity ranged between 1.30 and 1.58% citric acid and pH between 2.8 and 3.1. Selection 03/001 had the lowest SS value and it also had lower redness, but higher color saturation than 'Tupy' cultivar. The fatty acids found at higher concentration were palmitic (22-29%), oleic (13-32%) and linoleic acid (15-33%), with differences in the concentration among blackberry genotypes. The varieties of blackberry evaluated showed good nutritional value with sugar and acidity levels suitable for industrialization. It also contained fatty acids important for maintaining health.

Antioxidant capacity and composition of pitanga seeds / Capacidade antioxidante e composição de sementes de pitanga

Food industry generates a significant amount of seed wastes from the juice production, frozen pulps and jams. Considering that the characterization of wastes is the first step to determine their potential use, the aim of the present study was to determine the composition and the antioxidant capacity of seeds from pitanga fruits with different flesh colors (purple, red and orange). Chemical composition results revealed that pitanga seeds are a good source of insoluble dietary fiber, with low protein and fat levels, and no relevant differences were found among pitanga seeds from different flesh colors. Pitanga seed extracts had powerful antioxidant capacity that was partially correlated to their high phenolic content and showed some variation according to the pitanga flesh colors. Accordingly, it's suggested that this low value waste of pitanga processing, could be used as a source of natural antioxidants and dietary fiber, for animal and/or human nutrition.

A indústria de alimentos gera quantidades significativas de resíduos de sementes a partir da produção de sucos, polpas congeladas e geleias de frutas. Considerando que a caracterização dos resíduos é o primeiro passo para determinar o seu uso potencial, o objetivo do presente estudo foi determinar a composição e a capacidade antioxidante de sementes de pitanga com diferentes colorações de polpa (roxa, vermelha e laranja). Os resultados da composição química revelaram que as sementes de pitanga são boas fontes de fibra alimentar insolúvel, com níveis baixos de proteína e gordura, e sem diferenças relevantes entre as sementes de pitangas de diferentes colorações. Os extratos das sementes apresentaram uma excelente capacidade antioxidante, que foi parcialmente correlacionada com o alto teor de fenólicos e apresentou alguma variação de acordo com a coloração da polpa das pitangas. Assim, sugere-se que esse resíduo de baixo valor, resultante do processamento da pitanga, poderia ser utilizado como fonte de antioxidantes naturais e de fibra alimentar, para a nutrição humana e/ou animal.