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

Abstract

The cultivar Annurca is an apple that is cultivated in southern Italy that undergoes a typical redding treatment and it is appreciated for organoleptic characteristics, high pulp firmness, and nutritional profile. In this study, the effects of three different biostimulants (Micro-algae (MA), Protein hydrolysate (PEP), and Macro-algae mixed with zinc and potassium (LG)), with foliar application, on the quality parameters of Annurca apple fruits at the harvest, after redding, and at +60 and +120 days of cold storage were analyzed: total soluble solids (TSS) content, total acidity (TA), pH, firmness flesh, and red coloration of epicarp. Additionally, the polyphenolic quali-quantitative profile of pulp and peel was analyzed by UHPLC-Q-Orbitrap HRMS and Folin-Ciocalteu and the antioxidant capacity with the methods 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric-reducing antioxidant capacity (FRAP). The results obtained suggest that biostimulants are involved in the regulation of the secondary metabolism of the treated plants, acting positively on the quality of the Annurca fruits and their nutritional value. Fruits treated with PEP have shown, during cold storage, a significantly higher content of total polyphenols in flesh and a higher concentration of phloretin xylo-glucoside and phloridzin (350.53 and 43.58 mg/kg dw respectively). MA treatment caused, at the same time, an enhancement of flavonols between 0.6–28% and showed the highest total polyphenol content in the peel after 60 and 120 days of cold storage, with 2696.048 and 2570.457 mg/kg dw, respectively. The long-term cold storage (120 days) satisfactorily maintained phenolic content of fruits deriving from MA and PEP application, in accordance with data that were obtained for peel, showed an increase of 7.8 and 5.8%, respectively, when compared to the fruits cold stored for 60 days. This study represents the first detailed research on the use of different types of biostimulants on the quality of the Annurca apple from harvest to storage.

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

“…For example, Kocira and colleagues, studying the effects resulting from the application of three different biostimulants from Ulva fasciata , Sargassum ilicifolium , and Gracilaria corticata on beans, reported not only an increase in yield, but also in the production of polyphenols and carotenoids [ 60 ]. Similar results were also described after the application of biostimulants on other plants, including Prunus armeniaca [ 14 ], Phaseolus vulgaris [ 61 ], Malus pumila [ 13 ], and Solanum lycopersicum [ 15 ].…”

“…Moreover, changes in current unsustainable agricultural practices into more sustainable procedures may not only contribute to food security but also to mitigating climate change [ 11 ]. In this context, the use of plant wastes as natural biostimulants has aimed to increase sustainable productivity, and quality of fruit has turned out to be one of the most attractive frontiers in the agronomic field [ 12 , 13 , 14 , 15 , 16 ]. Despite both the differences in the raw materials employed and the large variety of phytochemicals present in the various biostimulant formulations [ 17 ], their application in very small amounts seems to be enough to promote plant growth.…”

“…In particular, scientific evidence shows that treatment with biostimulants can affect plant growth processes by enhancing water and/or nutrient uptake [ 18 ], root and shoot growth [ 12 , 14 , 19 ], activity of key enzymes involved in primary or secondary metabolism [ 17 , 20 ], and plant antioxidant defense system [ 21 ]. Moreover, treatments with biostimulants seem to be able to positively affect fruit quality in terms of nutritional values and nutraceutical properties [ 13 , 14 , 15 , 16 ]. However, with the exception of few cases, the effects of biostimulant treatment on crops was mainly investigated at the seedling stage, or measuring plant physiological parameters under abiotic stresses [ 18 , 21 , 22 , 23 ].…”

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

“…Natural extracts can enhance the anthocyanin and phenolic content in crops as a result of the modulation of genes involved in the anthocyanin and flavonoid biosynthesis pathway [ 96 ]. The higher phenolic concentration and antioxidant capacity can be attributed as well to the presence of thiamine which evokes diverse genes that belong to the phenylpropanoid pathway with a resultant greater enhancement of secondary metabolites and antioxidant capacity [ 97 ]. The lower phenolic content may be associated with high nitrogen fertilisation [ 98 ].…”

“…Elevated antioxidant activities are essential for extending the shelf life and enhancing the nutritional quality of fresh food [ 97 ]. Phenolic compounds (e.g., carotenoids, anthocyanins, and flavonoids) have important health-related features and exhibit anticancer and antioxidant activities [ 102 , 103 ].…”