Embarking on a journey of vibrant flavors and wholesome nutrition, strawberries and tomatoes stand out as exceptional fruits, each boasting an impressive array of health benefits.
Embarking on a journey of vibrant flavors and wholesome nutrition, strawberries and tomatoes stand out as exceptional fruits, each boasting an impressive array of health benefits. Whether enjoyed in their natural form or transformed into invigorating beverages such as fruit juice, these fruits offer a delightful fusion of taste and well-being.
Strawberries are among the fruits with the highest concentrations of natural vitamins. It is rich in anthocyanin, antioxidants, phenolic acids, and tannins, in addition to vitamin C and organic acids. Strawberry juice is a popular fruit beverage because of its appealing shade, pleasant fragrance, and sweet-sour flavor.
The tomato is the second most significant fruit or vegetable crop after the potato. Tomatoes are abundant in vitamins A and C, fibre, and potassium, as well as phytosterols and bioactive compounds. On the basis of sensory assessment and taking into account the advantages of tomatoes, it is possible to combine them with additional additions to create a beverage.
Blending of two or more juices was done to improve the flavour and quality of a single juice.
Need for Treatment:
Fruit drinks have grown in popularity as a result of consumer attachment to nutritious products, and their commercialization has accelerated in recent years.
Freshly squeezed fruit drinks are becoming more popular due to their sensory and dietary advantages, but they spoil quickly and have a shorter expiration life. Fruit drinks can be a source of foodborne disease due to their contamination by a wide range of microbes. E. coli, Listeria monocytogenes, and Salmonella spp. are the most prevalent pathogenic strains that induce food poisoning.
Impact of conventional thermal treatment on juices:
Conventional thermal procedures are frequently used to preserve food for a long time, assure its safety, and extend the shelf life of fruit juices because the effects of microbes and enzymes can be delayed by these traditional heat processing methods.
However, the nutritional, sensory, and functional qualities of food are impacted by the general effect of heat. Pasteurization and other traditional techniques have been used in food plants to eliminate or decrease microbes in food products. Thermal treatment is commonly used to extend the shelf life of fruit and vegetable drinks by inactivating bacteria.
The physical and nutritional characteristics of the liquid are changed unfavorably by heat treatment at higher temperatures. As customer preferences shift towards non-processed juices, the creation of innovative methods, particularly for fruit juice preparation, is gaining steam. Consumer demand involves not only increasing storage life by reducing microbial and enzymatic reactions, but also maintaining natural traits while improving quality.
While conventional heat treatment is effective in solving food safety issues, there is growing concern about nutritional quality losses and the degradation of many heat-labile nutrients. Heat treatment necessitates the use of convection and conduction methods, making uniformity difficult to achieve with this method.
Objective:
- to assess the effects of US, TS, and heat treatment on juice quality as customer demand for safe, healthy foods develops.
- to maintain the physicochemical properties of the juice blend.
- to compare different treatment conditions and find out the most effective technique to preserve the overall quality of the juice blend.
Our Research:
This research was conducted at the National Institute of Food Science and Technology (NIFSAT), Faculty of Food, Nutrition, and Home Sciences, University of Agriculture, Faisalabad.
Treatment plan:
Individual effects of US and TS on the strawberry-tomato juice blend were investigated.
Materials and Methods:
1. Preparation of fruit juice:
- Pretreatment of raw materials
The strawberries and tomatoes were peeled, trimmed, washed, and crushed (in a juicer). Fresh juices were filtered using a muslin cloth to separate the pulp.
- Preparation of a strawberry-tomato juice blend:
Strawberry and tomato juices were combined in a 50:50 ratio. The sample was mixed with 100 ml of a mixture of 50 ml of strawberry juice and 50 ml of tomato juice. Then more treatments were applied.
- Thermal treatment (TT):
The juice mixture was placed in a 250-ml glass beaker, and a water bath was used to heat it for 4 minutes at 95–100 °C. Samples were processed in full darkness to prevent any light-induced influence.
- Ultrasonication (US) treatment:
The juices were exposed to a steady US frequency of 25 kHz (70%), for 5 and 10 min. Samples were processed in full darkness to prevent any light-induced influence.
- Thermosonication (TS) treatment:
TS treatment is carried out at two temperatures, 40 and 50°C, using an ultrasonic probe sonicator. Samples were processed in full darkness to prevent any light-induced influence. The blend was transferred into sterilized bottles for further examination.
2. Physicochemical analysis:
- pH value:
By using the pH meter, the pH of control and experiment samples was measured. The probe was inserted into the strawberry-tomato juice blend, and the reading was noted after a few minutes.
- Total soluble solids (TSS):
At room temperature, TSS was measured using a hand refractometer.
- Colour measurement:
The color analysis was performed by a Hunter colorimeter. The colour values of strawberry- tomato juice blend were measured by a colorimeter and the average values were calculated.
- Determination of total phenolic contents and total flavonoid contents:
With the help of the colorimetric Folin-Ciocalteu reagent, the TPC of the strawberry-tomato juice blend was determined spectrophotometrically. The principle for the determination of total phenolic content by spectrophotometer involves the use of the Folin-Ciocalteu method.
The spectrophotometric method was used to determine TFC.
3. Statistical Analysis:
The collected data was expressed as the mean SD (standard deviation).
Conclusion:
There are limited studies available on blended juices, so this research has demonstrated the nutritional benefits of US processing and TS of fruit juice blends. As a result, our research also describes the effects of US and TS on the properties of juice blends. So the conclusion is that US and TS are novel techniques that can improve the nutritional and functional profile of juice blends.
The results showed that both US and TS had a positive effect on juice blend quality. So both processes are superior to thermal treatment from a quality perspective. The results of this study revealed that the US treatment produced the best results, improved the overall quality of the strawberry-tomato juice blend, and can also be used for industrial purposes.