The influence of manganese on the formation of volatile components in grapes and wine
The influence of manganese
It is a well-known and understood fact that chemical nutrients affect the increase in the yield of agricultural crops. It is also evident that they influence the formation of certain quality indicators, such as the oil content in the seeds of oil crops, the sugar content in the root crops of sugar beets, or the protein content in the seeds of legumes.
However, can nutrients have a deeper impact on the chemical components of crop production, such as the accumulation of individual phenols, polyphenols, for example, flavonoids, or changes in the profile of essential oils? They can. One such element is manganese (Mn).
Manganese (Mn) is a key micronutrient for plant growth and fruit development. It has several functions that affect various aspects of the plant, for example, it directly influences:
- the plant’s phenotype – height and biomass;
- participates in chemical reactions as an enzyme cofactor – photosynthetic synthesis of pigments;
- the antioxidant activity of enzymes and the metabolism of polyphenols;
- regulation of physiological processes – photosynthesis and stress resistance.
Mn induces systemic acquired resistance to protect plants from pathogenic infections.
However, the availability of Mn decreases in alkaline soils, severely limiting plant root growth and crop productivity.
A crop that is quite sensitive to manganese deficiency is the grape.
Foliar (leaf) application of manganese is an effective method to eliminate its deficiency compared to applying Mn to the soil, precisely because of its high absorption rate.
In cereal crops, foliar application of MnSO4 increases its concentration in the grain and the plant yield.
Many researchers have reported in detail on the effect of Mn application on fruit quality, including chemical components – total soluble solids, reducing sugars (any sugar that is capable of acting as a reducing agent. In an alkaline solution, a reducing sugar forms an aldehyde or ketone, allowing it to act as a reducing agent, for example, in Benedict’s reagent) and titratable acidity, and physical morphology – hardness, weight, and size of fruits and post-harvest parameters.
It has recently been reported that high concentrations of Mn increase the accumulation of individual phenols and alter the essential oil profiles of common tansy plants (Tanacetum vulgare L.). Other studies have shown that foliar application of manganese positively regulates the accumulation of polyphenols in grapes and wine, especially flavonoids. However, limited research has been devoted to the effect of manganese fertilizers on the volatile profiles of grapes and the taste of wine.
A 2025 study by Ruihua Ren et al. was published, which was conducted in the commercial vineyards of the “Guanlan” winery (38.43°N, 106.03°E) in China. Foliar application of manganese was carried out on vineyards (Vitis vinifera) of the Cabernet Sauvignon variety. Three concentrations of MnSO4·H2O (low (L): 300 mg/L; medium (M): 1200 mg/L; and high (H): 2400 mg/L) and deionized water (control, CK) were used.
The vines were sprayed on a sunny afternoon (5–7 p.m.) with no wind or precipitation for the next 24 hours. For the research, three concentrations of MnSO4·H2O were used:
- low (L): 300 mg/L;
- medium (M): 1200 mg/L;
- high (H) – 2400 mg/L;
- and deionized water as a control (CK).
All treatments were applied one week before and one week after the first flowering. Meaning the rate was split into two applications. The grape harvest was collected when the soluble solids content reached 23°Brix. From the harvested vines, according to the methodology, juice and wine were produced, which were further analyzed for physicochemical and organoleptic indicators, with additional analysis of the volatile components of the grapes and wine, as well as the calculation of odor activity.
Additionally, a sensory tasting experiment was conducted in accordance with the principles of the 1975 Declaration of Helsinki. And adequate countermeasures were taken to eliminate any risks that might be encountered. The sensory tasting panel consisted of 20 experts, including 10 men and 10 women aged 30–55 from the College of Enology of the Northwest A&F University. The sensory characteristics test consisted of three parts:
- appearance (clarity and color),
- aroma (elegance and finesse, harmony, intensity and duration, development and complexity),
- and mouthfeel (balance, texture and structure, persistence and hierarchy, as well as retronasal aroma and finish).
The score for each sub-index ranged from 0 (worst) to 10 (best). All wine samples were randomly numbered and tested using a blind taste system at room temperature.
The key findings were as follows:
- Compared to the control plot where no fertilizers were applied. The grape clusters in the plots where manganese was applied ripened faster. In the treated vines, the alcohol content was higher compared to the control. The increased alcohol content is explained by the maturity of the grapes and the accumulation of sugar in the berries. This conclusion confirms previous studies (Fig. 1) with foliar application of boron, published in 2023 in the journal Food Research International by scientists from Brazil, who found that the application of boron led to an increase in the content of anthocyanins, hydroxycinnamic acids, and flavonols in grapes and induced phenolic metabolism in cells, modulated the phytochemical composition of wine. Increasing the content of anthocyanins and flavonols in wines, and affected the elemental composition.
- Foliar feeding with Mn significantly enhanced the aromatic properties of grapes and wine.
- Application of 1200 mg/L of Mn increased the intensity, duration, and harmony of the wine’s aroma.
- Key flavor compounds, such as ethyl acetate, which give floral and fruity notes to the wine, were observed in greater quantities in the variants with Mn application.
We, at Wonder, continuously keep our finger on the pulse of innovation and developments in science, so we provide our consumers with products that can not only increase yields but also induce improved formation of all indicators of crop production. Choose Wonder Leaf Mono Mn 11 and Wonder Leaf Mono B11 for the nutrition of your vineyards and experience the significant advantages in the taste and aroma of your wine.
Манган (Mn) є ключовим мікроелементом для росту рослин і розвитку плодів.
Figure 1. A diagram of the experiment on the application of boron for grape nutrition, and its effect on the physicochemical properties of berries and the organoleptic properties of wine.
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