Effects of Biostimulants on Annurca Fruit Quality and Potential Nutraceutical Compounds at Harvest and during Storage

Biostimulants: A sufficiently effective tool for sustainable agriculture in the era of climate change?

Climate change is currently considered as one of the main concerns of the agriculture sector, as it limits crop production and quality. Furthermore, the current context of global crisis with international political instability and war conflicts over the world is pushing the agriculture sector even more to urgently boost productivity and yield and doing so in a sustainable way in the current frame of climate change. Biostimulants can be an effective tool in alleviating the negative effects of environmental stresses to which plants are exposed, such as drought, salinity, heavy metals and extreme temperatures etc. Biostimulants act through multiple mechanisms, modifying gene expression, metabolism and phytohormone production, promoting the accumulation of compatible solutes and antioxidants and mitigating oxidative stress. However, it is important to keep in mind that the use and effect of biostimulants has limitations and must be accompanied by other techniques to ensure crop yield and quality in the current frame of climate change, such as proper crop management and the use of other sustainable resources. Here, we will not only highlight the potential use of biostimulants to face future agricultural challenges, but also take a critical look at their limitations, underlining the importance of a broad vision of sustainable agriculture in the context of climate change.

The effects of macro-algae supplementation on serum lipid, glycaemic control and anthropometric indices: A systematic review and meta-analysis of clinical trials

INTRODUCTION

Macro-algae products have been shown to ameliorate the metabolic disorders state. Thus, highlighting their function as supplementary therapeutic agents can be a novel strategy for clinical therapies. This systematic review and meta-analysis of clinical trials aimed to summarize the effect of macro-algae consumption on serum lipid profile, glycaemic control and anthropometric factors.

METHODS

In this systematic review and meta-analysis, a comprehensive search was performed for relevant studies published up to May 2023. The Cochran's Q test and I-square (I2 ) tests were used to evaluate heterogeneity across the included studies. The meta-analysis was conducted using random-effects model (DerSimonian and Laird), and weighted mean difference (WMD) was considered as the pooled effect size.

RESULTS

Out of 8602 papers in the initial screening, eight clinical trials with a total of 438 participants were included into this meta-analysis. The results indicated that macro-algae supplementation significantly decreased serum levels of total cholesterol (TC) (WMD = -6.7 mg/dL; 95% CI: -12.59, -0.80; item = 0.026) and low-density lipoprotein cholesterol (LDL-c) (WMD = -8.25 mg/dL; 95% CI: -15.38, -1.12; p-value = .023). There was an increase in level of high-density lipoprotein cholesterol (HDL-c) (WMD = 0.48 mg/dL; 95% CI: -2.05, 3.01; p-value = .71) which was not statistically significant. Macro-algae supplementation reduced body mass index (BMI) (WMD = -0.28 kg/m2 ; 95% CI: -0.96, 0.41; p-value = .426), weight (WMD = -0.39 kg; 95% CI: -3.6, 2.83; p-value = .81), waist circumference (WC) (WMD = -0.52 cm; 95% CI: -2.71, 1.66; p-value = .64), fasting blood sugar (FBS) (WMD = -1.95 mg/dL; 95% CI: -5.19, 1.28; p-value = .24) and HbA1c (WMD = -0.02%; 95% CI: -0.14, 0.09; p-value = .66) in intervention group.

CONCLUSIONS

This meta-analysis indicated that macro-algae supplementation significantly decreased TC and LDL-c level. It can also increase HDL-c level and reduce anthropometric indices and glycaemic control factors.

Evaluation of the Bio-Stimulating Activity of Lake Algae Extracts on Edible Cacti Mammillaria prolifera and Mammillaria glassii

The research aimed to test different seaweed extracts derived from three macroalgae representatives, namely, Rhodophyta, Chlorophyta and Phaeophyceae, as a bio-fertiliser for the growth of Mammillaria prolifera and Mammillaria glassii and the production of edible fruits. The experiments started in September 2021 and were conducted in the greenhouses of CREA-OF in Pescia (PT). Three different algae, namely, Hypnea cornuta (Rhodophyta), Ulva ohnoi (Chlorophyta), collected from the brackish lake Ganzirri, in Messina, and Sargassum muticum (Phaeophyceae) from Venice lagoon, were tested. The experimental trial showed a significant improvement in the agronomic parameters analysed for the growth and production of cactus plants and fruits treated with the selected algae. A significant increase was found in the sugar, vitamin A, vitamin C and vitamin E content of the fruits of treated plants. In particular, the thesis with Ulva ohnoi was the best for plant growth and fruit production with a higher sugar and vitamin content. This experiment confirms the algae's ability to stimulate soil microflora and microfauna, promoting nutrient uptake, participating in organic matter mineralisation processes and significantly influencing the nutraceutical compounds in the fruits.

Changes in the Phytochemical Profile and Antioxidant Properties of Prunus persica Fruits after the Application of a Commercial Biostimulant Based on Seaweed and Yeast Extract

Plant biostimulants are formulations that are experiencing great success from the perspective of sustainable agriculture. In this work, we evaluated the effect derived from the application of a biostimulant based on algae and yeast extracts (Expando^®) on the agronomic yield and nutraceutical profile of two different cultivars ("Sugar Time" and "West Rose") of Prunus persica (peach). Although, at the agronomic level, significant effects on production yields were not recorded, the biostimulant was able to reduce the ripening time, increase the fruit size, and make the number of harvestable fruits homogeneous. From a nutraceutical point of view, our determinations via spectrophotometric (UV/Vis) and chromatographic (HPLC-DAD-MS/MS) analysis showed that the biostimulant was able to boost the content of bioactive compounds in both the pulp (5.0 L/ha: +17%; 4.0 L/ha: +12%; 2.5 L/ha: +11%) and skin (4.0 L/ha: +38%; 2.5 L/ha: +15%). These changes seem to follow a dose-dependent effect, also producing attractive effects on the antioxidant properties of the fruits harvested from the treated trees. In conclusion, the biostimulant investigated in this work proved to be able to produce more marketable fruit in a shorter time, both from a pomological and a functional point of view.

Evaluation of Morphological, Qualitative, and Metabolomic Traits during Fruit Ripening in Pomegranate (Punica granatum L.)

Pomegranate is characterized by several local accessions and cultivars widespread across different countries, each with different bio-agronomic features. Physiological and biochemical processes occur during fruit ripening, leading to changes in size, color, and flavor, improving the fruit’s acceptability for the consumer. The aim of this study was to evaluate the changes in physico-chemical and nutritional traits of three Italian germplasm genotypes (‘Santa Lucia’, ‘Di Benedetto’, and ‘Arborea’) to determine the differences for these parameters both within the same cultivar during four ripening stages, and between individual cultivars in the same ripening stage. Morphological traits and fruit pigmentation showed variation during the ripening process, with higher values at the final stage. The highest fruit weight was detected in ‘Di Benedetto’ (392.19 g), while ‘Arborea’ displayed high juice content. Qualitative traits, such as soluble solids, increased until stage III, while titratable acidity values decreased during the ripening stage in ‘Di Benedetto’ and ‘Arborea’. In all three accessions, a reduction in the total polyphenols up to the III ripening stage was observed. Metabolomic analyses using 1H-NMR (proton nuclear magnetic resonance) showed a variation in citric acid and sugar content according to the ripening stage and accession considered. This study found high variability in nutraceutical traits among the analyzed pomegranates. The three pomegranate genotypes showed significant differences in qualitative and metabolomic characteristics. Principal component analysis revealed the main traits that contribute to the positive and negative correlations with PC1 and PC2, highlighting the great variability in the investigated pomegranate genotypes.

Effect of Botanical Extracts on the Growth and Nutritional Quality of Field-Grown White Head Cabbage (Brassica oleracea var. capitata)

Nutraceuticals and functional foods are gaining more attention amongst consumers interested in nutritious food. The consumption of foodstuffs with a high content of phytochemicals has been proven to provide various health benefits. The application of biostimulants is a potential strategy to fortify cultivated plants with beneficial bioactive compounds. Nevertheless, it has not yet been established whether the proposed higher plants (St. John’s wort, giant goldenrod, common dandelion, red clover, nettle, and valerian) are appropriate for the production of potential bio-products enhancing the nutritional value of white cabbage. Therefore, this research examines the impact of botanical extracts on the growth and nutritional quality of cabbage grown under field conditions. Two extraction methods were used for the production of water-based bio-products, namely: ultrasound-assisted extraction and mechanical homogenisation. Bio-products were applied as foliar sprays to evaluate their impact on total yield, dry weight, photosynthetic pigments, polyphenols, antioxidant activity, vitamin C, nitrates, micro- and macroelements, volatile compounds, fatty acids, sterols, and sugars. Botanical extracts showed different effects on the examined parameters. The best results in terms of physiological and biochemical properties of cabbage were obtained for extracts from common dandelion, valerian, nettle, and giant goldenrod. When enriched with nutrients, vegetables can constitute a valuable component of functional food.

Assessment of In Vitro Bioaccessibility of Polyphenols from Annurca, Limoncella, Red Delicious, and Golden Delicious Apples Using a Sequential Enzymatic Digestion Model

Four different varieties of apples have been considered (Limoncella, Annurca, Red Delicious, and Golden Delicious) to estimate the extent of colon polyphenolics release after in vitro sequential enzyme digestion. Since several studies report a positive effect of apple polyphenols in colonic damage, we found of interest to investigate the colon release of polyphenols in different varieties of apples in order to assess their prevention of colonic damage. UHPLC-HRMS analysis and antioxidant activity (ABTS, DPPH, and FRAP assays) were carried out on the apple extracts (peel, flesh, and whole fruit) obtained from not digested samples and on bioaccessible fractions (duodenal and colon bioaccessible fractions) after in vitro digestion. Polyphenolic content and antioxidant activities were found to vary significantly among the tested cultivars with Limoncella showing the highest polyphenol content accompanied by an excellent antioxidant activity in both flesh and whole fruit. The overall trend of soluble antioxidant capacity from the soluble duodenal phase (SDP) and soluble colonic phase (SCP) followed the concentrations of flavanols, procyandinis, and hydroxycinnamic acids under the same digestive steps. Our results highlighted that on average 64.2% of the total soluble antioxidant activity was released in the SCP with Limoncella exhibiting the highest values (82.31, 70.05, and 65.5%, respectively for whole fruit, flesh, and peel). This result suggested that enzymatic treatment with pronase E and viscozyme L, to reproduce biochemical conditions occurring in the colon, is effective for breaking the dietary fiber-polyphenols interactions and for the release of polyphenols which can exercise their beneficial effects in the colon. The beneficial effects related to the Limoncella consumption could thus be of potential great relevance to counteract the adverse effects of pro-oxidant and inflammatory processes on intestinal cells.

Potential of Pre-Harvest Wastes of Tobacco (Nicotiana tabacum L.) Crops, Grown for Smoke Products, as Source of Bioactive Compounds (Phenols and Flavonoids)

Tobacco cultivation is characterized by high amounts of waste biomasses whose disposal frequently represents a complex and expensive problem. A study was conducted to evaluate thepotential of pre-harvest light air-cured (Burley) and dark fire-cured (Kentucky) tobacco waste biomasses as a source of bioactive compounds (nutraceutical ingredients) such as polyphenols. Pre-harvest waste materials (topping fresh materials and residual stalks at final harvest) were collected to determine dry matter, total polyphenols content (TPC; Folin assay), and DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,20-azino-bis(3-ethylbenzothiazoline-60-sulfonic acid) diammonium salt) antioxidant capacity. Polyphenols quali-quantitative profiles obtained by Orbitrap Q Exactive of both tobacco types were also determined. Total pre-harvest waste biomass amounted to 3956.9 and 1304.4 kg d.w. ha−1 in light air-cured (Burley) and dark fire-cured (Kentucky) tobacco types, respectively. Polyphenols content, expressed as g kg−1 dry weight (d.w.), ranged between 4.6 and 15.7 g kg−1 d.w. and was generally greater in leaves than in stalks. Considering both leaves and stalks, the light air-cured (Burley) tobacco crop yielded 22.1 kg ha−1 of polyphenols, while the dark fire-cured (Kentucky) tobacco yielded 12.0 kg ha−1. DPPH and ABTS were significantly greater in leaves than in stalks waste biomass in both types of tobacco. The most abundant components were quinic and chlorogenic acids, rutin, and luteolin rutinoside.

The Application of a Plant Biostimulant Based on Seaweed and Yeast Extract Improved Tomato Fruit Development and Quality

Plant biostimulants are under investigation as innovative products to improve plant production and fruit quality, without resulting in environmental and food contaminations. Here, the effects of the application of Expando, a biostimulant based on seaweed and yeast extracts, on plant productivity, fruit ripening times, and fruit quality of Solanum lycopersicum var. Micro-Tom were evaluated. After biostimulant treatment, a two-week reduction of ripening times and a concomitant enhancement of the production percentage during the earliest ripening times, in terms of both fruit yield (+110%) and size (+85%), were observed. Concerning fruit quality, proximate analysis showed that tomatoes treated with the biostimulant had better nutritional composition compared to untreated samples, since both the quality of unsatured fatty acids (C16:3ω3: +328%; C18:2ω6: -23%) and micronutrients essential for human health (Fe: +14%; Cu: +21%; Zn: +24%) were increased. From a nutraceutical point of view, despite strong changes in bioactive compound profile not being observed, an increase of the antioxidant properties was recorded in fruits harvested by plants treated with the biostimulant (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS): +38%; 2,2-diphenyl-1-picrylhydrazyl (DPPH): +11%). In conclusion, the biostimulant application was able to reduce the ripening times and fruit size, while slightly increasing nutritional and nutraceutical values, leading to more marketable tomato fruits.

Changes in Phenolics and Fatty Acids Composition and Related Gene Expression during the Development from Seed to Leaves of Three Cultivated Cardoon Genotypes

Cultivated cardoon (Cynara cardunculus var. altilis) has long been used as a food and medicine remedy and nowadays is considered a functional food. Its leaf bioactive compounds are mostly represented by chlorogenic acids and coumaroyl derivatives, known for their nutritional value and bioactivity. Having antioxidant and hepatoprotective properties, these molecules are used for medicinal purposes. Apart from the phenolic compounds in green tissues, cultivated cardoon is also used for the seed oil, having a composition suitable for the human diet, but also valuable as feedstock for the production of biofuel and biodegradable bioplastics. Given the wide spectrum of valuable cardoon molecules and their numerous industrial applications, a detailed characterization of different organs and tissues for their metabolic profiles as well as an extensive transcriptional analysis of associated key biosynthetic genes were performed to provide a deeper insight into metabolites biosynthesis and accumulation sites. This study aimed to provide a comprehensive analysis of the phenylpropanoids profile through UHPLC-Q-Orbitrap HRMS analysis, of fatty acids content through GC-MS analysis, along with quantitative transcriptional analyses by qRT-PCR of hydroxycinnamoyl-quinate transferase (HQT), stearic acid desaturase (SAD), and fatty acid desaturase (FAD) genes in seeds, hypocotyls, cotyledons and leaves of the cardoon genotypes “Spagnolo”, “Bianco Avorio”, and “Gigante”. Both oil yield and total phenols accumulation in all the tissues and organs indicated higher production in “Bianco Avorio” and “Spagnolo” than in “Gigante”. Antioxidant activity evaluation by DPPH, ABTS, and FRAP assays mirrored total phenols content. Overall, this study provides a detailed analysis of tissue composition of cardoon, enabling to elucidate value-added product accumulation and distribution during plant development and hence contributing to better address and optimize the sustainable use of this natural resource. Besides, our metabolic and transcriptional screening could be useful to guide the selection of superior genotypes.