Influence of culinary process on free and bound (poly)phenolic compounds and antioxidant capacity of artichokes

Impact of thermal processing on polyphenols, carotenoids, glucosinolates, and ascorbic acid in fruit and vegetables and their cardiovascular benefits

Bioactive compounds in fruit and vegetables have a positive impact on human health by reducing oxidative stress, inflammation, and the risk of chronic diseases such as cancer, cardiovascular (CV) diseases, and metabolic disorders. However, some fruit and vegetables must be heated before consumption and thermal processes can modify the amount of nutraceuticals, that is, polyphenols, carotenoids, glucosinolates, and ascorbic acid, that can increase or decrease in relation to different factors such as type of processing, temperature, and time but also the plant part (e.g., flower, leaf, tuber, and root) utilized as food. Another important aspect is related to the bioaccessibility and bioavailability of nutraceuticals. Indeed, the key stage of nutraceutical bioefficiency is oral bioavailability, which involves the release of nutraceuticals from fruit and vegetables in gastrointestinal fluids, the solubilization of nutraceuticals and their interaction with other components of gastrointestinal fluids, the absorption of nutraceuticals by the epithelial layer, and the chemical and biochemical transformations into epithelial cells. Several studies have shown that thermal processing can enhance the absorption of nutraceuticals from fruit and vegetable. Once absorbed, they reach the blood vessels and promote multiple biological effects (e.g., antioxidant, anti-inflammatory, antihypertensive, vasoprotective, and cardioprotective). In this review, we described the impact of different thermal processes (such as boiling, steaming and superheated steaming, blanching, and microwaving) on the retention/degradation of bioactive compounds and their health-promoting effects after the intake. We then summarized the impact of heating on the absorption of nutraceuticals and the biological effects promoted by natural compounds in the CV system to provide a comprehensive overview of the potential impact of thermal processing on the CV benefits of fruit and vegetables.

Artichoke By-Product Extracts as a Viable Alternative for Shelf-Life Extension of Breadsticks

The upcycling of agricultural by-products and the extension of the shelf-life of staple foods represent crucial strategies for mitigating the consequences of food losses and enhancing the competitiveness of the agri-food industry, thus facilitating the attainment of higher financial revenues. This is particularly relevant for global artichoke cultivation, where 60-80% of its biomass is discarded annually. The present study investigated the potential of using non-stabilized polyphenol-rich extracts from the main artichoke by-products (bracts, leaves, and stems) to fortify and extend the shelf-life of breadsticks. The incorporation of hydroalcoholic extracts at two addition levels (1000-2000 ppm) resulted in an increased antioxidant capacity and oxidative stability of fortified breadsticks. Rheological tests revealed that the fortification did not affect the dough's workability, with the exception of the leaf extract. While a slight deterioration in texture was observed, the shelf-life of breadsticks was significantly extended, particularly at the highest levels of addition, without any visible alteration in their appearance. The stem extract demonstrated the most promising outcomes, exhibiting a maximum increase of 69% in antioxidant capacity (DPPH) and an extension of the estimated shelf-life by 62% in the resulting breadsticks, prompting the potential for utilizing them to develop nutritious and healthy snacks with extended shelf-life.

Polysaccharide-polyphenol interactions: a comprehensive review from food processing to digestion and metabolism

Most studies on the beneficial effects of polyphenols on human health have focused on polyphenols extracted using aqueous organic solvents, ignoring the fact that a portion of polyphenols form complexes with polysaccharides. Polysaccharides and polyphenols are interrelated, and their interactions affect the physicochemical property, quality, and nutritional value of foods. In this review, the distribution of bound polyphenols in major food sources is summarized. The effect of food processing on the interaction between polyphenols and cell wall polysaccharides (CWP) is discussed in detail. We also focus on the digestion, absorption, and metabolic behavior of polysaccharide-polyphenol complexes. Different food processing techniques affect the interaction between CWP and polyphenols by altering their structure, solubility, and strength of interactions. The interaction influences the free concentration and extractability of polyphenols in food and modulates their bioaccessibility in the gastrointestinal tract, leading to their major release in the colon. Metabolism of polyphenols by gut microbes significantly enhances the bioavailability of polyphenols. The metabolic pathway and product formation rate of polyphenols and the fermentation characteristics of polysaccharides are affected by the interaction. Furthermore, the interaction exhibits synergistic or antagonistic effects on the stability, solubility, antioxidant and functional activities of polyphenols. In summary, understanding the interactions between polysaccharides and polyphenols and their changes in food processing is of great significance for a comprehensive understanding of the health benefits of polyphenols and the optimization of food processing technology.

Manufacture and characterization of a novel dairy-free quinoa yogurt fermented by modified commercial starter with Weissella confusa

Non-dairy yogurt is increasingly thought to be healthy food. However, no suitable starters limit its development. This study aimed to develop a novel and functional quinoa yogurt with a modified commercial starter. Compared with the other lactic acid bacteria (LAB), Weissella confusa showed a better fermentation performance of quinoa utilization. The synergistic effect of W. confusa and the commercial starter promoted the growth of LAB. It increased the fermentation rate of quinoa yogurt, further improving its texture, rheological properties, and storage stability. The modified starter significantly increased the nutritional qualities of the quinoa yogurt, including polyphenol content, antioxidant activity, digestive enzyme inhibition, and reduced postprandial blood glucose ability. Additionally, the modified starter enhanced the digestibility and bioaccessibility of polyphenols, protein, and fat in fermented quinoa yogurt. Overall, the commercial starter with W. confusa showed great potential for possible application in quinoa yogurt development.

Artichoke Industrial Waste in Durum Wheat Bread: Effects of Two Different Preparation and Drying Methods of Flours and Evaluation of Quality Parameters during Short Storage

'Violetto di Ramacca' is a local variety of artichoke grown in Sicily (Southern Italy), known for its purple color with green streaks. In this study, the effects of two different preparation and drying methods (method A, fresh sample oven-dried at 40 °C for 48 h then mixed and ground into flour; and B, minced and frozen sample oven-dried at 40 °C for 24 h then blended and ground into flour) for flours from different parts of the artichoke (bracts, stems, and mix), used at different percentages of integration (5, 7.5, and 10%), in combination with re-milled semolina, have been evaluated. The polyphenol contents of the flours produced with the two methods were measured. The results showed significant differences between the methods and samples, with a range from 9.09 mg GAE/g d.m. (bracts 100%, method A) to 2.62 mg/g (mix 100%, method B). The values were then lowered in the flour products with supplements ranging from 0.96 mg GAE/g (bract flour 10%, method A) to 0.11 mg GAE/g (mixed flour 7.5%, method B). As the amounts of polyphenols increased, the antioxidant activity increased, with a range that varied in the pure flour from 8.59 mg trolox eq/g d.m. (bract flour, method A) to 3.83 mg trolox eq/g d.m. (mixed flour, method B). These flours were also analyzed for color, highlighting a clear difference between methods A (greener) and B (browner). The flours thus obtained were used to produce breads, which were evaluated for their physicochemical characteristics during 4 days of storage. The results showed a reduction in volumes and heights, an increase in the percentage of integration of the artichoke flours, a greater quantity of moisture in the integrated breads, and a lower reduction in the structural characteristics during storage compared to the control breads. The TPA was conducted on the breads from T0 to T4, highlighting that, although initially more compact, the integrated breads offered less alteration of the values during storage. The aw ranged from 0.63 (mix flour 5%, method B) to 0.90 (bract flour 5%, method B). The amounts of polyphenols (from 0.57 mg GAE/g in bread with bracts at 10% (method A) to 0.13 mg GAE/g in bread with mix 5% (method B)) and the antioxidant activity (from 0.55 mg trolox eq/g d.m. in bread with bract flour 10% (method A) to 0.14% mg trolox eq/g d.m. in bread with mix flour) were also evaluated, showing a trend similar to the values obtained in the flours. Colorimetric tests highlighted a color more similar to wholemeal bread in the loaves produced with method B. Statistical factor analysis and cluster analysis were conducted for all trials.

LC-MS/MS Analysis Elucidates the Different Effects of Industrial and Culinary Processing on Total and Individual (Poly)phenolic Compounds of Piquillo Pepper (Capsicum annuum cv. Piquillo)

Pepper constitutes an important source of (poly)phenols, mainly flavonoids. Nevertheless, heat treatments applied prior to consumption may have an impact on these antioxidants, and thus may also affect their potential bioactivity. In this study, the effect of industrial and culinary treatments on the total and individual (poly)phenolic content of Piquillo pepper (Capsicum annuum cv. Piquillo) was thoroughly evaluated by high-performance liquid chromatography coupled to tandem mass spectrometry. A total of 40 (poly)phenols were identified and quantified in raw pepper. Flavonoids (10 flavonols, 15 flavones, and 2 flavanones) were the major compounds identified (62.6%). Among the 13 phenolic acids identified in raw samples, cinnamic acids were the most representative. High temperatures applied and subsequent peeling during industrial grilling drastically decreased the total (poly)phenolic content from 2736.34 to 1099.38 μg/g dm (59.8% reduction). In particular, flavonoids showed a higher reduction of 87.2% after grilling compared to nonflavonoids which only decreased by 14%. Moreover, 9 nonflavonoids were generated during grilling, modifying the (poly)phenolic profile. After culinary treatments, specifically frying, (poly)phenols appear to be better released from the food matrix, enhancing their extractability. Overall, industrial and culinary treatments differently affect both the total and individual (poly)phenolic compounds of pepper and, despite the reduction, they might also positively influence their bioaccessibility.

Ready-to-Use Nutraceutical Formulations from Edible and Waste Organs of Algerian Artichokes

Edible, plant-derived foodstuffs are recognized as precious sources of polyphenol compounds, whose consumption has proven to have multiple beneficial effects on human health. However, the awareness that cooking processes are able to induce quali-quantitatively changes in their native occurrence and that their bioavailability after food ingestion is poor led the research to move toward the preparation of nutraceutical supplements aimed at maximizing their content by effective extractive techniques and protecting them from degradation. The present work fits into this context, proposing a green, ready-to-use formulation of capitula, stems, and leaves of Algerian artichokes, in which natural deep eutectic solvents were exploited as extracting solvents but not removed at the end of the process. MTT test on the Caco-2 cell line highlighted that mitochondrial redox activity inhibition was absent below the 50 µg/mL tested dose. Simulated in vitro digestion was used as a predictive model for formulation bioaccessibility, where the joint approach with UHPLC-HRMS techniques allowed to define the release of each polyphenol from the investigated matrices. The capitula-based sample was the richest one in flavonoids, especially luteolin and apigenin glycosides, which survived in the intestinal digesta. On the contrary, simple phenols characterized the stem sample, whose release was mainly in the gastric chyme.

Seasonal Fluctuations of Crop Yield, Total Phenolic Content and Antioxidant Activity in Fresh or Cooked Borage (Borago officinalis L.), Mallow (Malva sylvestris L.) and Buck’s-Horn Plantain (Plantago coronopus L.) Leaves

The interest for wild edible plants as functional food is increasing among consumers in the Mediterranean countries because of their high content of antioxidants. However, a critical point is the seasonality of wild edible species due to their spontaneity and the cultivation results necessary to satisfy market requests. Moreover, cooking may be necessary for most wild edible species to enhance their palatability. In the present experiment, the crop yield, total phenolic content (TPC) and antioxidant activity (AA) of leaves were determined in three wild edible species (Borago officinalis L., Malva sylvestris L. and Plantago coronopus L.), which were hydroponically cultivated in winter and in spring. Plants were recurrently harvested three times and the leaves were analyzed raw or after boiling in water for different times based on their palatability as evaluated by a hedonic test (2 min for B. officinalis, 2.5 min for M. sylvestris and 8 min for P. coronopus). The total crop yield was promising, especially for P. coronopus, with small differences between winter and spring (9.3 and 13.8 kg m−2, respectively). The boiling treatment caused a loss of TPC and, in some cases, of the AA in B. officinalis and M. sylvestris due to the solubilization of phenolic and other antioxidant compounds in boiling water. Conversely, in P. coronopus, TPC and AA were higher in boiled leaves than in fresh leaves, likely due to the strong binding of phenolic compounds to the cell wall. This binding might lead to the inefficient extraction of these compounds through the boiling treatment.