**4. Nondestructive determination of tomato fruit in different ripening stages — Techniques to analyse properties and quality of plants**

From an agricultural point of view, the optimal picking time for tomatoes is when 85% -90% of the fruits are red or almost red. Typically, tomato fruits are harvested when they are light red in colour. Such fruits are less injured mechanically during the harvesting process. It is known that tomato colour depends on the pigment (lycopene, carotene, xanthophylls, and chlorophyll) concentration and distribution, so the proper time of tomato picking affects the overall fruit and yield quality. The optimal colour of tomato fruits is when they are rich in carotenoids and low in carotene. Fruits that are harvested too early have a poorer quality because organic and mineral accumulation in their tissues is not finished. Such fruits are entirely unsuitable for storage. Therefore, fruit picking time is determined by the size, colour, texture and flesh firmness [2, 72].

Producers focus their attention on fruit and vegetable quality and aim to avoid poor quality production. The genotype of selected cultivars has a great influence on fruit quality, but the degree of maturity is also very important. Packaging factories use ethylene gas (natural fruit hormone) to speed up the tomato ripening processes. It has been established that during the fruit ripening process, ethylene gas is produced naturally. It increases the permeability of the cell protoplasm. Ethylene then enters the cell, and the air activates the biochemical processes of ripening. Therefore, in order to speed up the ripening of fruit, ethylene gas is employed. The action of ethylene helps to ripen tomatoes within 4-6 days, under the same conditions without ethylene gas fruit maturation time is nearly three times longer [73, 74].

Growers select commercial tomato varieties and hybrids that are resistant to diseases and pests in order to obtain more high-quality fruits. However, picking tomato fruits before they are technically mature may have a decisive influence on their final quality and taste. Commercial growers are concerned with producing adequate amounts of high-quality products, but they are not as concerned about fruit taste; however, tomato flavour is one of the most important indicators for consumers [2, 69].

In tomatoes, individual elements of biochemical composition are typically determined by chemical analysis methods (spectroscopy, high performance liquid chromatography, thin layer chromatography, and so on). Carotenoid (lycopene and β-carotene) extraction from tomato as well as its biochemical analysis requires a large quantity of various organic solvents. Lycopene extraction with organic solvents is a good method for qualitative and quantitative analysis, but this extraction method is not cost-efficient and is time consuming [75, 76]. To facilitate and simplify the determination of biochemical substances without tomato damage, it may be possible to use nondestructive methods, such as colour coordinate spectrophotom‐ etry and near-infrared (NIR) spectroscopy method based on the transmittance principle, using near-infrared wavelength spectrophotometer.

Biochemical analyses using modern detection methods require not only specialised and expensive equipment but also professional and technical personnel, causing many inconven‐ iences for growers, producers, and researchers. Agriculture, plant breeding, and food industry should use a simple, inexpensive, reliable, and rapid method for the detection of biochemical substances in tomatoes [77, 78]. Therefore, attention has been given to three-dimensional colorimetry, where the assessment of reflection values is rescaled and compared with the values of biochemical elements. The nondestructive prediction of individual biochemical elements is very important in tomato breeding and in the development of new varieties to improve fruit quality, because it is possible to predict the amount of biochemical elements on the plant without fruit damage. This could significantly speed up the process of selection and hybridisation [79, 80].

**4. Nondestructive determination of tomato fruit in different ripening**

From an agricultural point of view, the optimal picking time for tomatoes is when 85% -90% of the fruits are red or almost red. Typically, tomato fruits are harvested when they are light red in colour. Such fruits are less injured mechanically during the harvesting process. It is known that tomato colour depends on the pigment (lycopene, carotene, xanthophylls, and chlorophyll) concentration and distribution, so the proper time of tomato picking affects the overall fruit and yield quality. The optimal colour of tomato fruits is when they are rich in carotenoids and low in carotene. Fruits that are harvested too early have a poorer quality because organic and mineral accumulation in their tissues is not finished. Such fruits are entirely unsuitable for storage. Therefore, fruit picking time is determined by the size, colour,

Producers focus their attention on fruit and vegetable quality and aim to avoid poor quality production. The genotype of selected cultivars has a great influence on fruit quality, but the degree of maturity is also very important. Packaging factories use ethylene gas (natural fruit hormone) to speed up the tomato ripening processes. It has been established that during the fruit ripening process, ethylene gas is produced naturally. It increases the permeability of the cell protoplasm. Ethylene then enters the cell, and the air activates the biochemical processes of ripening. Therefore, in order to speed up the ripening of fruit, ethylene gas is employed. The action of ethylene helps to ripen tomatoes within 4-6 days, under the same conditions

Growers select commercial tomato varieties and hybrids that are resistant to diseases and pests in order to obtain more high-quality fruits. However, picking tomato fruits before they are technically mature may have a decisive influence on their final quality and taste. Commercial growers are concerned with producing adequate amounts of high-quality products, but they are not as concerned about fruit taste; however, tomato flavour is one of the most important

In tomatoes, individual elements of biochemical composition are typically determined by chemical analysis methods (spectroscopy, high performance liquid chromatography, thin layer chromatography, and so on). Carotenoid (lycopene and β-carotene) extraction from tomato as well as its biochemical analysis requires a large quantity of various organic solvents. Lycopene extraction with organic solvents is a good method for qualitative and quantitative analysis, but this extraction method is not cost-efficient and is time consuming [75, 76]. To facilitate and simplify the determination of biochemical substances without tomato damage, it may be possible to use nondestructive methods, such as colour coordinate spectrophotom‐ etry and near-infrared (NIR) spectroscopy method based on the transmittance principle, using

Biochemical analyses using modern detection methods require not only specialised and expensive equipment but also professional and technical personnel, causing many inconven‐ iences for growers, producers, and researchers. Agriculture, plant breeding, and food industry

without ethylene gas fruit maturation time is nearly three times longer [73, 74].

**stages — Techniques to analyse properties and quality of plants**

texture and flesh firmness [2, 72].

60 Plants for the Future

indicators for consumers [2, 69].

near-infrared wavelength spectrophotometer.

Prediction accuracy depends on the amount of accurate accumulated data, which is obtained by chemical analysis. Therefore, it is important to collect a large database of research results so that predicted data would more closely resemble observed data [75, 79].

For that reason, a study of tomato fruit ripening processes was conducted, and calibration curves for dry matter, soluble solids, organic acids, skin and flesh firmness, lycopene and βcarotene, ascorbic acid, and sugar content were created according to data from NIR and biochemical analysis methods. The investigation looked at different tomato cultivars of different fruit ripening stages. The study examined 10 different tomato cultivars and hybrids including 'Tamina', 'Money Maker', 'Saint Pierre', 'Tocayo H', 'Polfast H', 'Brooklyn H', 'Tolstoi H.', 'Benito H', 'Tourist H', and 'Rutuliai'. In order to get more and varied types of data, the dynamics of biochemical elements during fruit ripening were also observed. There‐ fore, the tomato fruit investigations were made with fruits of six different ripening stages [80].

During the investigation, tomato fruit biochemical composition and texture analysis were conducted using near-infrared (NIR) spectroscopy performed in parallel with normal bio‐ chemical and texture analyses. It assessed the values of reflection (nondestructive method) compared with the biochemical and fruit texture values (destructive methods).

During the first year of the experiment, calibration graphs were created, and the statistical reliability of these graphs was evaluated during the second year.

Biochemical analyses were conducted using the following methods. Ascorbic acid was determined by titration with 2.6-dichloroindophenol sodium salt solution, soluble solids were determined with a digital refractometer (ATAGO, PAL-1, Japan), dry matter by gravimetri‐ cally after drying at 105°C to a constant weight, and sugars by the AOAC method. Organic acid content, expressed as citric acid, was determined by titration with a 0.1-N sodium hydroxide solution, and carotenoids were measured using HPLC.

Tomato texture was measured using a texture analyser (TA.XTPlus, Stable Micro Systems, Godalming, United Kingdom). To pierce the tomato peel and the pulp of the fruit (unpeeled skin), a P/2 probe (2 mm diameter flat probe tip) was used, and the data were processed using 'Texture Exponent' software.

The near-infrared (NIR) spectroscopy method, based on transmittance, was used for nondes‐ tructive measurements, using a near-infrared wavelength spectrophotometer (NIR Case NCS001A, SACM SCImola Imola, Italy).

Calibration graphs were created using 'SACM NCS (NIR Calibration Software) Vers. 3.0 RC 1' software.

Calibration graphs of dry matter, soluble solids, organic acids, skin and flesh firmness, lycopene and β-carotene, ascorbic acid, and sugar content were created according to NIR and chemical analysis data. The created graphs make it possible to determine the amount of these elements in a nondestructive manner. The tomato skin firmness calibration graph is shown in Fig. 15.

**Figure 15.** Calibration graph of tomato skin firmness.

Such calibration graphs allow the determination of the strength of the tomato fruit and amount of biochemical elements very quickly and inexpensively, and also offers great opportunities to producers, manufacturers, and food industry.

On the second year of the study, the reliability of the newly created calibration graphs was assessed. Again, normal biochemical analysis and nondestructive measurements using nearinfrared (NIR) spectroscopy were performed. The reliability of the obtained results was evaluated statistically (Table 3).

Based on the obtained results, a strong correlation between normal and nondestructive analytical methods in measuring of soluble solids (*r* = 0.9251), lycopene (*r* = 0.8701), β-carotene (*r* = 0.9486), ascorbic acid (*r* = 0.8052), skin strength (*r* = 0.9906) and the pulp strength (*r* = 0.9369) was found. The average correlation was observed in dry matter (*r* = 0.6480), titratable acidity (*r* = 0.5800), and total sugars (*r* = 0.5982). Consequently, based on the created calibration graphs, nondestructive measurements of tomato fruit quality parameters using near-infrared spectro‐ scopy (NIR) can be carried out. The reliability assessment of the obtained results and compar‐ ison of nondestructive techniques and traditional methods showed that there is a strong correlation between them by measuring soluble solids, lycopene, β-carotene, ascorbic acid, skin firmness and strength of the flesh, and average correlation by determining dry matter, titratable acidity, and total sugar content of tomato fruits.

Biochemical Parameters in Tomato Fruits from Different Cultivars as Functional Foods for Agricultural, Industrial... http://dx.doi.org/10.5772/60873 63


**Table 3.** Reliability of investigated parameters

Calibration graphs were created using 'SACM NCS (NIR Calibration Software) Vers. 3.0 RC

Calibration graphs of dry matter, soluble solids, organic acids, skin and flesh firmness, lycopene and β-carotene, ascorbic acid, and sugar content were created according to NIR and chemical analysis data. The created graphs make it possible to determine the amount of these elements in a nondestructive manner. The tomato skin firmness calibration graph is shown in

Such calibration graphs allow the determination of the strength of the tomato fruit and amount of biochemical elements very quickly and inexpensively, and also offers great opportunities

On the second year of the study, the reliability of the newly created calibration graphs was assessed. Again, normal biochemical analysis and nondestructive measurements using nearinfrared (NIR) spectroscopy were performed. The reliability of the obtained results was

Based on the obtained results, a strong correlation between normal and nondestructive analytical methods in measuring of soluble solids (*r* = 0.9251), lycopene (*r* = 0.8701), β-carotene (*r* = 0.9486), ascorbic acid (*r* = 0.8052), skin strength (*r* = 0.9906) and the pulp strength (*r* = 0.9369) was found. The average correlation was observed in dry matter (*r* = 0.6480), titratable acidity (*r* = 0.5800), and total sugars (*r* = 0.5982). Consequently, based on the created calibration graphs, nondestructive measurements of tomato fruit quality parameters using near-infrared spectro‐ scopy (NIR) can be carried out. The reliability assessment of the obtained results and compar‐ ison of nondestructive techniques and traditional methods showed that there is a strong correlation between them by measuring soluble solids, lycopene, β-carotene, ascorbic acid, skin firmness and strength of the flesh, and average correlation by determining dry matter,

1' software.

62 Plants for the Future

Fig. 15.

**Figure 15.** Calibration graph of tomato skin firmness.

evaluated statistically (Table 3).

to producers, manufacturers, and food industry.

titratable acidity, and total sugar content of tomato fruits.
