Chemical and Microbiological Evaluation of Dried Tomato slices for Nigerian System

Abstract

Tomato (Lycopersicon esculentum) is regarded as one of the most important vegetable crops grown all over the world and Nigeria in particular, after onions and pepper [1]. In Nigeria, tomato accounts for about 18% of the average daily consumption of vegetables [2].Tomatoes are a good source of vitamin C and vitamin A equivalents (in the form of β-carotene) and provide some vitamin E, folic acid, potassium and other trace elements. One of the most well-known tomatoes eating benefits is its lycopene content. Lycopene is a vital anti-oxidant that helps in the fight against cancerous cell formation as well as other kinds of health complications and diseases. Diets that include tomato have been linked with reduced risk of obesity and some neurological diseases including Alzheimer's disease.Nigeria is ranked the second largest producer of tomato in Africa and 13 th in the world [3]. Due to lack of post-harvest enterprise and poor post-harvest storage plans, Nigeria is unable to meet its domestic demands for tomatoes even though it ranks 13 th on the world tomato production hierarchy. The high moisture content of tomato makes their handling, transportation and marketing a problem especially in the tropics [4]. Tomatoes deteriorate rapidly after harvest, requiring preservation and/or processing in other to extend its shelf life.Drying tomatoes is one of the easiest known preservation methods. The amount of time it takes to dry tomatoes depends on the tomato variety, the air's humidity during the drying process, the thickness of the tomato slices or pieces, and the efficiency of the dehydrator or oven. Traditionally, drying has been used as a method of preserving foodstuffs in Nigeria and other developing countries [5]. Drying basically removes moisture from food and this inhibits the growth of bacteria and fungi. Moreover, it slows down the enzyme action without deactivating them. These factors ensure that food does not spoil easily and hence, makes drying an effective food preservation technique.Since tomato is seasonal, preservation is important to minimize wastage and spoilage during the tomato producing season and to ensure that maximum nutritional contents of the fruits are retained. The success of such effort would lead to the development

Convective Hot Air Drying of Chilli Pepper: Process Optimization and Modelling the Drying Kinetics and Quality Attributes of Dried Product

“…for convective tray drying of apple,Shishir et al (2016) for the spray drying of pink quava, and Taheri-Garavand and Meda (2018) for the hot air drying of savory leaves. Similarly, a decrease in microbial load as a result of increase in drying temperature has also been observed and reported for the drying of green onions(Garcia et al, 2010;Martinazzo et al, 2016) and tomato(Dauda et al, 2019;Ochida et al, 2019). Furthermore, run numbers 1 and 9, 2 and 10, 3 and 11, 4 and 12, 5 and 13, 6 and 14, 7and 15, 8 and 16, 23 and 24, and 23 and 25 were carried out at the same drying conditions of air velocity, relative humidity and drying temperature, however, at different drying time (D) and the results illustrates that both the PMC and TPC decreased as the drying time increased from low level of 180 min (coded value -1) to high level of 360 min (coded value +1) as better represented by a diagnostic perturbation plot presented inFig.…”

“…These corresponding values are lower than the value of 5.70×10 5 cfu/g obtained for the fresh chilli pepper. The differences observed between the values for the dried product and the fresh product may be attributed to the synergistic effects of thermal inactivation and dehydration inactivation based on temperature intensity, drying environment characteristic (such as relative humidity, pressure, air velocity etc) and drying time (Bourdoux et al, 2016;Dauda et al, 2019). The high moisture content which invariably means high water activity of the fresh chilli pepper might be responsible for the high TPC or microbial load.…”

“…Few studies as ascertained from literature have been done to investigate and evaluate the effects of pretreatment, drying methods, and temperature on the microbial load (or survival of microorganisms) of dried fruits and vegetables such as green onions, tomato, carrots, apple and cabbage (Garcia et al, 2010;Sohail et al, 2011;Martinazzo et al, 2016;Bourdoux et al, 2016;Dauda et al, 2019;Ochida et al, 2019). However, the effects or impacts of drying process conditions such as air velocity and relative humidity on the chilli drying process as well as on the quality attributes like nutritional properties (i.e.…”

Maintaining the freeze thawing characteristics of tomato through development and evaluation of magnetic field‐assisted freezing system

“…Other preservation techniques have been already applied by various scientists like sun drying, oven drying, spray drying, etc. Dauda et al (2019), conducted an experiment to evaluate the microbiological and chemical properties of dried tomato slices. Sliced tomato samples were subjected to sun drying and oven drying at 40, 50, and 60°C with a uniform thickness of 7 mm.…”

Drying Process Optimization and Modelling the Drying Kinetics and Quality Attributes of Dried Chili Pepper (Capsicum frutescens L.)

“…Moreover, few number of studies as obtained from the literature have been conducted to investigate the effects of pretreatment, temperature, and methods of drying on the microbial load of dried green onions, tomato, carrots, and apple [51][52][53]. However, to the best of our knowledge, the effects of drying temperature at varying levels of air velocity and relative humidity on the microbiological (microbial load) quality attributes of the dried chili pepper have not been investigated.…”