MEASURING COMMERCIAL TOMATO QUALITY
Tomatoes are in high demand because the world population consumes them daily. This research aims to improve tomato production and fruit quality through fruit measurement methods, which have a low impact factor on the fruit and plant during measurements. In the present paper, we present a review of the main attributes, such as color, ripening rate, firmness, shape, size and composition, that determine tomato fruit quality for final consumers; we also overview the methods (invasive destructive and invasive nondestructive) currently used to evaluate these attributes. The future trend in attribute analysis involves the development of portable, low-cost devices that take images directly from crops in the field to instantly determine quality characteristics.
Influencing Tomato Quality
During the later stages of growth it is particularly important to ensure that environmental and growth constraints do not limit quality potential. For example, the resultant color, aroma, flavor and texture are all established at this stage of development.
Maintaining steady growth of fruit at all times will ensure good quality criteria are met.
Reducing glasshouse temperatures can slow ripening. A fruit ripening agent can be applied a couple of weeks prior to harvest in processed tomatoes to ensure even maturity. It can also be promoted by treating harvested green fruit with ethylene or ethephon.
Control of pests and diseases, and maintenance of a controlled irrigation regime throughout fruit fill, will help maintain skin and internal fruit texture with minimal disorders.
The minimization of fruit disorders will also ensure good crop quality:
Blossom End Rot (BER) will be minimized by avoiding large fluctuations in water deficits. Mulching to conserve moisture in field tomato crops can help.
Similarly, in a greenhouse environment, maintaining a steady transpiration rate through night and day humidity control can help reduce the incidence of BER.
Blotchy ripening is more common under low light or heavy vegetative growth due to low temperatures, excess of water, or low salinity. It can be minimized by changing the irrigation regime (amount and EC) and by leaf pruning.
Sunscald can be reduced by increasing leaf shading of the fruit by careful water and crop protection management techniques. Increased planting density and variety choice can also help.
Cracking and russeting of the fruit is made worse by fluctuations in water supply.
Puffiness is associated with low light and low temperature conditions. Thinning, and preventing prolific vegetative growth or shading can minimize this disorder.
Crop nutrition is essential. Fertilizer programs starting early during establishment and vegetative growth are needed to ensure nutrients don’t limit fruit quality:
High potassium supply decreases puffiness. Too much nitrogen increases the disorder and can slow ripening.
Maintaining high potassium and nitrogen levels in the fruit will minimize blotchiness and greenback problems in fruit.
Potassium and nitrogen are important for aroma. Too much ammonium-N adversely affects taste.
Potassium is the main nutrient affecting the quality of the tomato, improving the uniformity of ripening, shape, acidity and taste of the fruit.
High levels of calcium are important in maintaining firmness and preventing damages due to disorders or during handling and transportation.
Maintaining high levels of calcium in the root zone and throughout the plant, minimizing the impact of competing cations such as ammonium, will reduce BER incidence.
Low levels of boron can lead to corkiness of the fruit and poor marketable quality.
Zinc also has a role to play in maintaining fruit quality.
TOMATO QUALITY TESTING
Tomato quality is a multi-faceted trait, involving many processes at the plant and fruit level, which depend on interactions between cultural practices, genetic and environmental factors. This review focusses on tomato quality as influenced by pre-harvest factors, and quality is defined from the consumer’s point of view, i.e. through fruit size or fresh mass, colour, taste, flavour, texture and health value. Tomato is a model plant for biologist and the second fruit consumed worldwide. The mechanisms involved in tomato fruit quality have been extensively investigated by physiologists and geneticists, and the responses to climatic and cultural practices have been widely described. Yet, our ability to manage and improve fruit quality in a context of global change will rely on our capacity to integrate knowledge’s and anticipate interactions among genotype, environment and cultural practices. The recent development of process-based models of fruit quality may help us for this challenging issue. Several models of tomato growth and quality are reviewed here, as well as their potential application for the design of ideotypes, i.e. conceptual plants that are expected to perform in specific environments.
Tomato - A. Composition of Tomato Fruit & Quality Characteristics
In the USA, the tomato is called ‘the poor man’s orange‘ because of its low price and high concentrations of vitamin C, as well as citric and malic acid.
In many areas of the South they could call orange as ‘the poor man’s tomato‘ because of their sometimes unjustified or justifiably high price.
But either in the South or in the North, the nutritional value of tomatoes is recognized as significant. The last few years have been flourishing the research about the medicinal uses of its fruit.
Starting from the composition of the tomato fruit and its qualitie characteristics will be attempted in a series of articles presenting these aspects of tomato, others that rank fruit and others in vegetables, but all agree that it is called tomato.
Except for a member of the editorial team. This member believes, after excessive alcohol consumption, that there is no agreement about the name. His disagreement is recorded and he is delivered to the lions.
Tomato – A. Composition of Tomato Fruit & Quality Characteristics
Composition of Tomato Fruit - Standard Type Tomatoes on the Plant
Standard Type Tomatoes on the Plant
Defining Quality Characteristics
The quality characteristics of tomato fruits are determined mainly by color, texture and flavor. These characteristics are directly related to both the variety and the method of cultivation as well as the conditions under which it is carried out.
For example, the composition of tomato fruit of the same variety will differ with respect to the quality characteristics depending on whether it is cultivated on or off the ground.
However, the high quality of tomato is mainly related to the redness of the color and the intensity of the taste. The taste and color of the tomato, on the other hand, are determined by the sugar content of the fruit. Research has shown that when the sugar content of tomato is at its peak then the skin of the fruit gets the strongest and most intense red color due to the dominance of the pigment called lycopene.
Tomato – A. Composition of Tomato Fruit & Quality Characteristics
Composition of Tomato Fruit - Standard Type of Tomatoes in Outdoor Cultivation
Standard Type of Tomatoes in Outdoor Cultivation
Composition of Tomato Fruit - Standard Type Tomatoes
Standard Type Tomatoes
Composition of Tomato Fruit - Sugars & Carbohydrates
One of the above mentioned about sugars is to start presenting the ingredients that are of importance to the composition of tomato fruit from them.
Free sugars account for more than 60% of the solid ingredients in tomatoes. They are mainly represented by D-glucose and D-fructose as well as by sucrose, although sucrose has a minimal contribution (0.5-1.5%).
The content of the remaining carbohydrates is very little starch, dextrin (0.06-0.2%), hemicellulose (0.1-0.2%) as well as cellulose (0.16-0.31%).
Specifically for starch, it should be noted that the content of the tomato fruit in it depends on the variety, cultivar, and ripening conditions.
In general, starch in tomato ranges from 1-1.22% to immature fruits reaching up to 0.1-0.15% in red-ripe fruit.
Tomato – A. Composition of Tomato Fruit & Quality Characteristics
Composition of Tomato Fruit - Standard Type Tomatoes
Standard Type Tomatoes in Different Ripening Stages
Composition of Tomato Fruit - Standard Type Greenhouse Tomatoes
Standard Type Greenhouse Tomatoes
Composition of Tomato Fruit - Pectins, Ascorbic Acid & Vitamins
The percentage of pectin involvement affects and co-shapes the texture of the tomato fruit. Thus, the tomato has a satisfactory texture only when pectase, pectin and calcium are present in sufficient amounts. Pectin averages 3.9% of the dry substance of the tomato fruit.
Tomatoes contain large amounts of vitamins. Vitamin C is detected at a rate ranging from 2 to 50%. On the basis of the fresh weight, the tomato content of vitamin C is on average about 25 mg / 100 g.
However, the values of ascorbic acid show this range because its presence varies according to the variety of cultivated tomato. From the point of view of physiological processes, studies have shown that tomato varieties ripening at a faster rate contain higher amounts of vitamin C than those whose ripening is relatively slow.
In addition to vitamin C, tomato contains large amounts of carotene, B vitamins (B1, B2, B3, B6, B9), vitamin H as well as inositol.
The relationship between the vitamins contained in the tomato fruit and the lions has not yet been adequately researched. Perhaps Bob Marley with ‘Iron Lion Zion’ has something to say about it.
TOMATO QUALITY DETERMINATION
Tomato is one of the most widely consumed fresh vegetables in the industrialized world and an important source of healthy constituents of the human diet. Despite the unique flavor characteristics of tomatoes, which make them extremely valuable in cooking, and their recognized beneficial role in the diet, the quality of tomato was traditionally only considered in connection to external appearances. As it happened with other highly requested crops, breeding programs of tomato focused their efforts on developing new varieties with higher yields and stress resistance, with better uniformity in fruit size, brighter color and prolonged shelf life. The downside of these strategies was that organoleptic features and nutritional value were often neglected, with a detrimental effect on commercial tomatoes. Over the last years, there has been an increase in consumers’ demand for tasty and healthy products. This aspect, paired with novel and multidisciplinary approaches to tomato research, allowed both sensory and nutritional qualities to be reconsidered as valuable parameters in breeding. In this review we describe the main chemical constituents of tomato, focusing on the flavor compounds (both volatile and non-volatile compounds) and secondary metabolites. Particular attention is paid to their beneficial effects on human health and their relevance to the overall quality of tomato.
Tomato fruit quality is determined mainly by color, texture, and flavor. Among those, color and flavor are probably the most useful criteria for estimating maturity of tomato fruit. High quality is associated with redness of color and prominence of flavor. ... By use and culture, the tomato is considered a vegetable.
Red Beefsteak Tomatoes
Green Beefsteak Tomatoes
Tomatoes On The Vine
Tomatoes 101: Nutrition Facts and Health Benefits
The tomato (Solanum lycopersicum) is a fruit from the nightshade family native to South America.
Despite botanically being a fruit, it’s generally eaten and prepared like a vegetable.
Tomatoes are the major dietary source of the antioxidant lycopene, which has been linked to many health benefits, including reduced risk of heart disease and cancer.
They are also a great source of vitamin C, potassium, folate, and vitamin K.
Usually red when mature, tomatoes can also come in a variety of colors, including yellow, orange, green, and purple. What’s more, many subspecies of tomatoes exist with different shapes and flavor.
This article tells you everything you need to know about tomatoes.
The water content of tomatoes is around 95%. The other 5% consists mainly of carbohydrates and fiber.
Here are the nutrients in a small (100-gram) raw tomato (1Trusted Source):
Protein: 0.9 grams
Carbs: 3.9 grams
Sugar: 2.6 grams
Fiber: 1.2 grams
Fat: 0.2 grams
Carbs comprise 4% of raw tomatoes, which amounts to fewer than 5 grams of carbs for a medium specimen (123 grams).
Simple sugars, such as glucose and fructose, make up almost 70% of the carb content.
Tomatoes are a good source of fiber, providing about 1.5 grams per average-sized tomato.
Most of the fibers (87%) in tomatoes are insoluble, in the form of hemicellulose, cellulose, and lignin (2).
Fresh tomatoes are low in carbs. The carb content consists mainly of simple sugars and insoluble fibers. These fruits are mostly made up of water.
Vitamins and minerals
Tomatoes are a good source of several vitamins and minerals:
Vitamin C. This vitamin is an essential nutrient and antioxidant. One medium-sized tomato can provide about 28% of the Reference Daily Intake (RDI).
Potassium. An essential mineral, potassium is beneficial for blood pressure control and heart disease prevention (3Trusted Source).
Vitamin K1. Also known as phylloquinone, vitamin K is important for blood clotting and bone health (4Trusted Source, 5Trusted Source).
Folate (vitamin B9). One of the B vitamins, folate is important for normal tissue growth and cell function. It’s particularly important for pregnant women (6Trusted Source, 7Trusted Source).
Tomatoes are a good source of several vitamins and minerals, such as vitamin C, potassium, vitamin K, and folate.
Other plant compounds
The content of vitamins and plant compounds in tomatoes can vary greatly between varieties and sampling periods (8, 9Trusted Source, 10Trusted Source).
The main plant compounds in tomatoes are:
Lycopene. A red pigment and antioxidant, lycopene has been extensively studied for its beneficial health effects (11Trusted Source).
Beta carotene. An antioxidant that often gives foods a yellow or orange hue, beta carotene is converted into vitamin A in your body.
Naringenin. Found in tomato skin, this flavonoid has been shown to decrease inflammation and protect against various diseases in mice (12Trusted Source).
Chlorogenic acid. A powerful antioxidant compound, chlorogenic acid may lower blood pressure in people with elevated levels (13Trusted Source, 14Trusted Source).
Chlorophylls and carotenoids like lycopene are responsible for the rich color of tomatoes.
When the ripening process starts, the chlorophyll (green) is degraded and carotenoids (red) are synthesized (15Trusted Source, 16Trusted Source).
Lycopene — the most abundant carotenoid in ripened tomatoes — is particularly noteworthy when it comes to the fruit’s plant compounds.
It’s found in the highest concentrations in the skin (17Trusted Source, 18Trusted Source).
Generally, the redder the tomato, the more lycopene it has (19Trusted Source).
Tomato products — such as ketchup, tomato juice, tomato paste, and tomato sauces — are the richest dietary sources of lycopene in the Western diet, providing over 80% of dietary lycopene in the United States (20Trusted Source, 21Trusted Source).
Gram for gram, the amount of lycopene in processed tomato products is often much higher than in fresh tomatoes (22Trusted Source, 23Trusted Source).
For example, ketchup boasts 10–14 mg of lycopene per 3.5 ounces (100 grams), while one small, fresh tomato (100 grams) holds only 1–8 mg (24).
However, keep in mind that ketchup is often consumed in very small amounts. Thus, it may be easier to bump up your lycopene intake by eating unprocessed tomatoes — which also have far less sugar than ketchup.
Other foods in your diet may have a strong effect on lycopene absorption. Consuming this plant compound with a source of fat can increase absorption by up to four times (25Trusted Source).
However, not everyone absorbs lycopene at the same rate (26Trusted Source).
Even though processed tomato products are higher in lycopene, it’s still recommended to consume fresh, whole tomatoes whenever possible.
Lycopene is one of the most abundant plant compounds in tomatoes. It’s found in the highest concentrations in tomato products, such as ketchup, juice, paste, and sauce.
Health benefits of tomatoes
Consumption of tomatoes and tomato-based products has been linked to improved skin health and a lower risk of heart disease and cancer.
Heart disease — including heart attacks and strokes — is the world’s most common cause of death.
A study in middle-aged men linked low blood levels of lycopene and beta-carotene to increased risk of heart attacks and strokes (27Trusted Source, 28Trusted Source).
Increasing evidence from clinical trials suggests that supplementing with lycopene may help lower LDL (bad) cholesterol (29Trusted Source).
Clinical studies of tomato products indicate benefits against inflammation and markers of oxidative stress (30Trusted Source, 31Trusted Source).
They also show a protective effect on the inner layer of blood vessels and may decrease your risk of blood clotting (32Trusted Source, 33Trusted Source).
Cancer is the uncontrolled growth of abnormal cells that spread beyond their normal boundaries, often invading other parts of the body.
Observational studies have noted links between tomatoes — and tomato products — and fewer incidences of prostate, lung, and stomach cancers (34Trusted Source, 35Trusted Source).
While the high lycopene content is believed responsible, high-quality human research needed to confirm the cause of these benefits (36Trusted Source, 37Trusted Source, 38Trusted Source).
A study in women shows that high concentrations of carotenoids — found in high amounts in tomatoes — may protect against breast cancer (39Trusted Source, 40Trusted Source).
Tomatoes are considered beneficial for skin health.
Tomato-based foods rich in lycopene and other plant compounds may protect against sunburn (41Trusted Source, 42Trusted Source).
According to one study, people who ingested 1.3 ounces (40 grams) of tomato paste — providing 16 mg of lycopene — with olive oil every day for 10 weeks experienced 40% fewer sunburns (43Trusted Source).
Studies show that tomatoes and tomato products may reduce your risk of heart disease and several cancers. This fruit is also beneficial for skin health, as it may protect against sunburns.
Commercial ripening process
When tomatoes start to ripen, they produce a gaseous hormone called ethylene (44Trusted Source, 45Trusted Source).
Commercially grown tomatoes are harvested and transported while still green and immature. To make them red before selling, food companies spray them with artificial ethylene gas.
This process inhibits the development of natural flavor and may result in tasteless tomatoes (46).
Therefore, locally grown tomatoes may taste better because they’re allowed to ripen naturally.
If you buy unripened tomatoes, you can speed up the ripening process by wrapping them in a sheet of newspaper and keeping them on the kitchen counter for a few days. Just make sure to check them daily for ripeness.
Tomatoes are often harvested while still green and immature, then ripened artificially with ethylene gas. This may lead to less flavor development, resulting in bland tomatoes.
Safety and side effects
Tomatoes are generally well tolerated and tomato allergy is very rare (47Trusted Source, 48Trusted Source).
Although tomato allergy is rare, individuals allergic to grass pollen are more likely to be allergic to tomatoes.
This condition is called pollen-food allergy syndrome or oral-allergy syndrome (49Trusted Source).
In oral-allergy syndrome, your immune system attacks fruit and vegetable proteins that are similar to pollen, which leads to allergic reactions like itching in the mouth, scratchy throat, or swelling of the mouth or throat (50Trusted Source).
People with latex allergy can also experience cross-reactivity to tomatoes (51Trusted Source, 52Trusted Source).
Tomatoes are generally well tolerated but may cause allergic reactions in people allergic to grass pollen.
The bottom line
Tomatoes are juicy and sweet, full of antioxidants, and may help fight several diseases.
They are especially high in lycopene, a plant compound linked to improved heart health, cancer prevention, and protection against sunburns.
Tomatoes can be a valuable part of a healthy diet.
Written by Adda Bjarnadottir, MS, RDN (Ice) on March 25, 2019
Is a Tomato a Fruit or Vegetable?
Fruits vs Veggies
Tomatoes are quite possibly one of the summer season’s most versatile produce offerings.
They’re typically grouped alongside vegetables in the culinary world, but you