**3. The pro-health properties of blueberry fruits with a wide range of biological effects**

Highbush blueberry (*Vaccinium corymbosum*) fruit is a particularly rich source of antioxidants [34]. Those compounds are mainly represented by flavonoids including anthocyanins, flavonols and flavanols, and polyphenolic compounds, which are represented by phenolic acids, tannins and stilbenes [35], which have high antioxidant capacity against hydrogen peroxide, superoxide radicals, peroxyl radicals and singlet oxygen [36]. Many studies have indicated that the blueberry has several beneficial health properties associated with the presence of such bioactive compounds [37]. These compounds may play a crucial role in the prevention of many chronic diseases.

#### **3.1 Anthocyanin**

*Modern Fruit Industry*

Duke Spartan

Bluecrop Bluegold Calypso Draper Toro Valour

Chandler Lateblue

Aurora Last call Liberty

**Table 2.**

caries for years to come.

grew in the container.

success of the cultivation.

or peat should be used for every plant. If the soil is very compact, hindering the development of fine roots, coarse sand can be additionally introduced at a ratio of 2:1:1. This treatment lowers the pH of the substrate while providing the plants with

Early

Medium-early

Medium-late

Late

**Variety Ripening time**

*List of the most common varieties of commercial plantings in Poland.*

High blueberry shrubs, like other fruit plants, can be planted in autumn or spring. Each of these periods has its own advantages and disadvantages. The biggest disadvantage of autumn planting of shrubs is a possibility of freezing of shrubs in the winter. High blueberry shrubs are produced in containers (2–3 l pots) or root balled. Such material can be planted theoretically during the entire vegetation period, but the most often recommended time is the period of spring planting of plants. Regardless of the planting time, providing the plants with plenty of water should be always kept in mind. The material most commonly used to establish a plantation is 2 or 3 years old and has a well-developed root system. At commercial plantations, planting of blueberry shrubs is usually recommended with 3.0 × 1.0 m spacing. The belt and row planting system with 3.2 × 1.2 × 1.25 m spacing is used less frequently. Shrubs should be planted 2–3 cm deeper than they

In addition to the aforementioned factors related to land selection and soil preparation, the choice of variety is of great importance in the cultivation of blueberry. The value of a cultivated variety is determined by its biological properties and economic characteristics. Biological properties include the longevity of the shrubs, soil and climatic requirements, the time when the vegetation starts and ends, the time when the berries start to bear fruit, the fruitfulness and ripeness of the berries and resistance to diseases and pests. Equalisation of fruits, that is, their size and number of berries in the cluster and their taste and usable value, resistance of fruits to transport and durability in commodity trading are the economic features of significant importance. In our climatic zone, the varieties of North American origin are grown most often. Until recently, the leading variety most commonly found at plantations was the 'Bluecrop' variety, while nowadays such varieties as 'Liberty',

'Chandler', 'Duke' and 'Aurora' are most willingly planted (**Table 2**).

However, for the preparation of high blueberry plantation, the soil class is less important because the blueberry is an extremely resistant plant which has relatively low nutritional requirements. The appropriate quantity of water and regular enrichment of the settlement with humus using peat or sawdust guarantee the

**70**

Anthocyanins in blueberry fruits comprise a large group of water-soluble pigments. In fruits, they are found mainly in the external layers of the hypodermis (the skin). In cells, they are present in vacuoles in the form of various sized granules [38]. Anthocyanins are part of the very large and widespread group of plant constituents known collectively as flavonoids [39]. It has been found that blueberry anthocyanins may prevent multiple chronic diseases such as cancer [40], cardiovascular disease, diabetes [41] and age-related neurodegenerative decline [42]. Generally, anthocyanins have been reported to reduce damage caused by freeradical activity such as low-density lipoprotein oxidation, platelet aggregation and endothelium-dependent vasodilation of arteries [43]. The potential mechanisms by which anthocyanins may prevent colorectal cancer may relate to apoptosis induction and cell-cycle arrest as well as inhibition of proliferation, inflammation and angiogenesis [44].

#### **3.2 Polyphenolic compounds**

Polyphenols are a large class of natural compounds that have high antioxidant capacity and potential beneficial human health effects. These effects include antioxidant, anti-allergic, anti-inflammatory, anti-viral, anti-proliferative, antimutagenic, antimicrobial, anti-carcinogenic, protection from cardiovascular damage and allergy, microcirculation improvement, peripheral capillary fragility prevention, diabetes prevention and vision improvement [35, 45]. These classes of compounds also appear to have positive effects on the cardiovascular system, which may be due to their ability to act as free radical scavengers or by other mechanisms [46].

#### **3.3 Antioxidant activity**

Overproduction of reactive oxygen species (ROS), such as superoxide anion, hydrogen peroxide and peroxyl radicals, and reactive nitrogen species (RNS), such as nitric oxide and peroxynitrite radicals, could lead to oxidative stress and nitrosative stress, respectively. These reactive species can damage proteins, lipids and DNA, leading to lipid peroxidation, altered signal transduction pathways and the destruction of membranes and organelles [47]. The balance between ROS and antioxidants in biological systems is referred to as redox homeostasis [48]. In order to combat oxidative stress, there are several types of endogenous enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT) and peroxidases (POD), as well as nonenzymatic glutathione, ascorbate, carotenoids and polyphenolic compounds [47].

As a rich source of antioxidants, blueberry bioactive components exert an important role against oxidative insults [49]. The antioxidative activity of compounds found in blueberry fruits relies on various mechanisms, subject to their structure. Flavonoids inhibit lipid oxidation; they chelate metals and scavenge the active forms of oxygen [50]. Anthocyanins, which are a flavonoid subgroup, inhibit the oxidation of human low-density lipoprotein and liposomes and scavenge free radicals [51]. They are also the most effective natural antioxidants and are shown to have significant anti-ageing, anticancer and immunoprotective effects [52]. Glycosylation of an anthocyanin decreases radical scavenger activity compared with the aglycone, as it reduces the ability of the anthocyanin radical to delocalise electrons [53, 54]. Anthocyanins also protect ascorbic acid against oxidation [55]. Polyphenolic compounds protect the easily oxidisable food compounds. They inhibit the oxidation of vitamin C, carotenoids and unsaturated fatty acids [56]. Blueberry fruits also contain vitamin C, provitamin A, carotenoids and E and B vitamins that can contribute to antioxidant protection [57].

In addition, the anticancer effects of berry bioactive compounds reduce and repair damage resulting from oxidative stress and inflammation [58]. Those berry phytochemicals may also potentially sensitise tumour cells to chemotherapeutic agents by inhibiting pathways that lead to treatment resistance, and consumption may provide protection from therapy-associated toxicities. These include effects on cellular differentiation and apoptosis and effects on proteins and enzymes that are involved in these processes.

#### **3.4 Effects of blueberry fruit consumption on human health**

Blueberries constitute one of the most important sources of potential health supporting phytochemicals in the human diet [58]. The dietary consumption of berries has positive effects on human health and diseases [37, 39]. Blueberry fruits are a rich source of ascorbic acid and phenolic compounds, particularly phenolic acids, anthocyanins, proanthocyanidins and other flavonoids, which prove to be beneficial to human health [58]. Their biological activities include protection against the incidence and mortality rates of cancer and protection against ischemic heart disease mortality, and they have antitumourigenic, antimicrobial, anti-inflammatory allergic and antimutagenic properties. Therefore, the use of phytochemicals as dietary supplements is growing.

However, what dose of a single antioxidant should be used as a dietary supplement? Natural phytochemicals at the low levels present in fruit and vegetables offer health benefits, but these compounds may not be effective or safe when consumed at higher doses, even in a pure dietary supplement form. Generally, taking higher doses increases the risk of toxicity. In the case of antioxidant nutrients, the proper physiologic dose should follow the recommended dietary allowance [59]. The pharmacologic dose is not equal to the physiologic dose and in some cases can be toxic. For example, in a human study, 30 healthy individuals whose diets were supplemented with 500 mg vitamin C/dose showed an increase of oxidative damage in the DNA isolated from lymphocytes [48].

#### **4. Effect of factors on blueberry bioactive substances**

Many factors that may impact antioxidant activity and composition in blueberry fruits include cultivar, environmental conditions, degree of ripeness, storage and food processing.

**73**

*Soil Preparation, Running Highbush Blueberry (*Vaccinium corymbosum *L.) Plantation…*

It is known that the content of phenolic compounds in berry fruits is also affected by genetic differences among cultivars of *Vaccinium corymbosum* [60–62]. Similarly, there is considerable variability in the antioxidant capacity of different cultivars [63, 64]. The genotype and maturity have effects on the activity and composition of antioxidant compounds of whole, skin and pulp fruits from highbush blueberry. Total antioxidant activity and the content of bioactive compounds in ripe

The content of antioxidants in blueberries varied among the developmental stages of fruits. An increasing maturity at harvest of blueberry cultivars yielded fruits with higher antioxidant, anthocyanins and total phenolic contents [65, 66]. By contrast, Castrejón et al. found that polyphenolic compounds' concentration and antioxidant activity in highbush blueberry fruits decreased from unripe green to ripe blue stages of fruit maturity [67]. Total flavonoids and vitamin C levels in blueberry fruits were also decreased as the fruits grow [68]. Those antioxidants in green fruits were highest and blue fruits were lowest. Total phenolic contents and total flavonoids in fruit skin were much higher than in other tissues, which may

Additionally, total antioxidant activity in unripe green and fully ripe fruits was high, whereas the lowest levels were found in intermediate ripe fruits [63]. Obvious differences in the antioxidant enzyme activities were observed among different developmental stages of fruit and tissues [68]. In the skin, pulp and blue fruit, generally SOD, POD and CAT were the highest in the skin, followed by the blue fruit, and the pulp content was the lowest, while the opposite was found in the PPO. The antioxidant enzyme activities in fruit are mainly influenced by species, environmental conditions, fruit maturation, variability over the years, harvest season and

Blueberry fruits are commercialised in different ways, mainly as fresh or frozen products. Freezing and drying are two possible methods to preserve blueberries, but the severity of both processes might destroy anthocyanins or their antioxidant

The bioactive compounds in highbush blueberry fruits can be stored only for 6 weeks under controlled atmospheric conditions, in which none of the cultivars showed a significant decrease from the harvest antioxidant activity value in

In the condition of storage at 5°C, the level of bush ripeness had no significant effect on antioxidant activity, total phenolic content or anthocyanin content; however, fruit maturity had a significant effect on antioxidant activity, total phenolic content and anthocyanin content. The content of those bioactive substances was strongly correlated with each other. An increase in antioxidant activity, total phenolic content and anthocyanin content may occur in blueberry during cold storage and

The influence of storage conditions on anthocyanin stability for blueberries stored frozen was also investigated. Concentration of anthocyanins in frozen blueberries was significantly reduced; more than 50% degradation of the anthocyanins

indicate that the skin has the higher antioxidant performance.

*DOI: http://dx.doi.org/10.5772/intechopen.89071*

fruits varied among the cultivars.

**4.2 Degree of ripeness**

other factors.

effects [69].

fruits [70].

**4.3 Storage condition**

is cultivar dependent [61, 62].

**4.1 Cultivars**

*Soil Preparation, Running Highbush Blueberry (*Vaccinium corymbosum *L.) Plantation… DOI: http://dx.doi.org/10.5772/intechopen.89071*

#### **4.1 Cultivars**

*Modern Fruit Industry*

involved in these processes.

dietary supplements is growing.

in the DNA isolated from lymphocytes [48].

**4. Effect of factors on blueberry bioactive substances**

As a rich source of antioxidants, blueberry bioactive components exert an important role against oxidative insults [49]. The antioxidative activity of compounds found in blueberry fruits relies on various mechanisms, subject to their structure. Flavonoids inhibit lipid oxidation; they chelate metals and scavenge the active forms of oxygen [50]. Anthocyanins, which are a flavonoid subgroup, inhibit the oxidation of human low-density lipoprotein and liposomes and scavenge free radicals [51]. They are also the most effective natural antioxidants and are shown to have significant anti-ageing, anticancer and immunoprotective effects [52]. Glycosylation of an anthocyanin decreases radical scavenger activity compared with the aglycone, as it reduces the ability of the anthocyanin radical to delocalise electrons [53, 54]. Anthocyanins also protect ascorbic acid against oxidation [55]. Polyphenolic compounds protect the easily oxidisable food compounds. They inhibit the oxidation of vitamin C, carotenoids and unsaturated fatty acids [56]. Blueberry fruits also contain vitamin C, provitamin A, carotenoids and E and B

In addition, the anticancer effects of berry bioactive compounds reduce and repair damage resulting from oxidative stress and inflammation [58]. Those berry phytochemicals may also potentially sensitise tumour cells to chemotherapeutic agents by inhibiting pathways that lead to treatment resistance, and consumption may provide protection from therapy-associated toxicities. These include effects on cellular differentiation and apoptosis and effects on proteins and enzymes that are

Blueberries constitute one of the most important sources of potential health supporting phytochemicals in the human diet [58]. The dietary consumption of berries has positive effects on human health and diseases [37, 39]. Blueberry fruits are a rich source of ascorbic acid and phenolic compounds, particularly phenolic acids, anthocyanins, proanthocyanidins and other flavonoids, which prove to be beneficial to human health [58]. Their biological activities include protection against the incidence and mortality rates of cancer and protection against ischemic heart disease mortality, and they have antitumourigenic, antimicrobial, anti-inflammatory allergic and antimutagenic properties. Therefore, the use of phytochemicals as

However, what dose of a single antioxidant should be used as a dietary supplement? Natural phytochemicals at the low levels present in fruit and vegetables offer health benefits, but these compounds may not be effective or safe when consumed at higher doses, even in a pure dietary supplement form. Generally, taking higher doses increases the risk of toxicity. In the case of antioxidant nutrients, the proper physiologic dose should follow the recommended dietary allowance [59]. The pharmacologic dose is not equal to the physiologic dose and in some cases can be toxic. For example, in a human study, 30 healthy individuals whose diets were supplemented with 500 mg vitamin C/dose showed an increase of oxidative damage

Many factors that may impact antioxidant activity and composition in blueberry fruits include cultivar, environmental conditions, degree of ripeness, storage and

vitamins that can contribute to antioxidant protection [57].

**3.4 Effects of blueberry fruit consumption on human health**

**72**

food processing.

It is known that the content of phenolic compounds in berry fruits is also affected by genetic differences among cultivars of *Vaccinium corymbosum* [60–62]. Similarly, there is considerable variability in the antioxidant capacity of different cultivars [63, 64]. The genotype and maturity have effects on the activity and composition of antioxidant compounds of whole, skin and pulp fruits from highbush blueberry. Total antioxidant activity and the content of bioactive compounds in ripe fruits varied among the cultivars.

#### **4.2 Degree of ripeness**

The content of antioxidants in blueberries varied among the developmental stages of fruits. An increasing maturity at harvest of blueberry cultivars yielded fruits with higher antioxidant, anthocyanins and total phenolic contents [65, 66]. By contrast, Castrejón et al. found that polyphenolic compounds' concentration and antioxidant activity in highbush blueberry fruits decreased from unripe green to ripe blue stages of fruit maturity [67]. Total flavonoids and vitamin C levels in blueberry fruits were also decreased as the fruits grow [68]. Those antioxidants in green fruits were highest and blue fruits were lowest. Total phenolic contents and total flavonoids in fruit skin were much higher than in other tissues, which may indicate that the skin has the higher antioxidant performance.

Additionally, total antioxidant activity in unripe green and fully ripe fruits was high, whereas the lowest levels were found in intermediate ripe fruits [63]. Obvious differences in the antioxidant enzyme activities were observed among different developmental stages of fruit and tissues [68]. In the skin, pulp and blue fruit, generally SOD, POD and CAT were the highest in the skin, followed by the blue fruit, and the pulp content was the lowest, while the opposite was found in the PPO. The antioxidant enzyme activities in fruit are mainly influenced by species, environmental conditions, fruit maturation, variability over the years, harvest season and other factors.

#### **4.3 Storage condition**

Blueberry fruits are commercialised in different ways, mainly as fresh or frozen products. Freezing and drying are two possible methods to preserve blueberries, but the severity of both processes might destroy anthocyanins or their antioxidant effects [69].

The bioactive compounds in highbush blueberry fruits can be stored only for 6 weeks under controlled atmospheric conditions, in which none of the cultivars showed a significant decrease from the harvest antioxidant activity value in fruits [70].

In the condition of storage at 5°C, the level of bush ripeness had no significant effect on antioxidant activity, total phenolic content or anthocyanin content; however, fruit maturity had a significant effect on antioxidant activity, total phenolic content and anthocyanin content. The content of those bioactive substances was strongly correlated with each other. An increase in antioxidant activity, total phenolic content and anthocyanin content may occur in blueberry during cold storage and is cultivar dependent [61, 62].

The influence of storage conditions on anthocyanin stability for blueberries stored frozen was also investigated. Concentration of anthocyanins in frozen blueberries was significantly reduced; more than 50% degradation of the anthocyanins was found after 6 months of frozen storage [71]. However, when drying was preceded with osmotic dehydration, a small amount of anthocyanins in blueberry fruits were lost [69].

## **4.4 Food processing**

Many fruit-based foods are processed into products such as beverages, baked goods or confectionaries. Processing and preservation methods, such as hot air drying, freezing/thawing, freezing/osmotic pretreatment and microwave drying, are popular techniques for blueberry fruit preservation [72]. The processing treatments that the fruit undergo may have a detrimental effect on their phytochemical antioxidant.

Regarding the influence of processing methods, the antioxidant capacity is decreased by food processing practices, such as heat or aeration [60]. There was a slight increase in anthocyanin content of the highbush blueberry fruit when processed at 20°C; however, there was no change in the oxygen radical absorbing capacity. A slight increase in total anthocyanin value after some thermal pretreatment processing was recorded [73]. Blanching of blueberries at 85°C for 3 min resulted in about 7% growth of anthocyanin. However, the anthocyanin content of thermally treated blueberries, osmodehydrated, or air dried at 70°C decreased by about 30% [74]. The amount of anthocyanins after freeze-drying is also lower probably due to their degradation.

The antioxidant capacity of the blueberries was superior. The pomace exhibited high activity, albeit lower than that of the fruit; however, after processing, the flour and the dried blueberries lost 66 and 46% of the original antioxidant activity, respectively [75]. The average anthocyanin contents of the fruits were moderate compared to other sources and species of blueberries. The pomace contains a large amount of anthocyanins, while the flour and dried blueberries exhibited a 32 and 42% loss in anthocyanin content, respectively.

**75**

**Author details**

and Iwona Morkunas4

\*, Szymon Cieśliński1

\*

, Van Chung Mai2

1 Department of Dendrology, Pomology and Nursery Production, Faculty of Horticulture and Landscape Architecture, Poznań University of Life Sciences,

2 Department of Plant Physiology, Faculty of Biological Sciences, University of

3 Department of Horticulture, Faculty of Agriculture, University of Cukurova,

4 Department of Plant Physiology, Faculty of Horticulture and Landscape

iwona.morkunas@gmail.com and iwona.morkunas@mail.up.poznan.pl

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Architecture, Poznań University of Life Sciences, Poznań, Poland

\*Address all correspondence to: zofia.zydlik@up.poznan.pl;

provided the original work is properly cited.

, Nesibe Ebru Kafkas3

Zofia Zydlik1

Poznań, Poland

Adana, Turkey

Vinh, Vinh, Vietnam

*Soil Preparation, Running Highbush Blueberry (*Vaccinium corymbosum *L.) Plantation…*

*DOI: http://dx.doi.org/10.5772/intechopen.89071*

*Soil Preparation, Running Highbush Blueberry (*Vaccinium corymbosum *L.) Plantation… DOI: http://dx.doi.org/10.5772/intechopen.89071*
