Quality and Physiochemical Properties of Banana Paste under Vacuum Dehydration

Abstract

This research aimed to develop a prototype of an evaporative dehydrator and demonstrate the effect of quick evaporative dehydration on the physiochemical properties of banana paste. The study was divided into 2 parts. The first part was focused on the development of the evaporative dehydrator prototype. After several modifications, the prototype of an evaporative dehydrator was successfully constructed to enable the variation of banana paste sample prior to evaporation using two types of evaporative stresses (i.e., atmospheric and vacuum conditions). The second part was to study the effect of evaporative dehydration on the physiochemical properties of banana paste comparing vacuum and atmospheric conditions. The temperature setting for the heating section was varied at 30, 40, 60, 80, 100 and 120 degree Celsius and the physiochemical alteration of the banana paste sample was monitored. The peroxidase enzyme was found to be active in all treatments. The evaporative cooling in the vacuum treatment caused the temperature of the final product to be lower than that of the atmospheric treatment. The moisture content also seemed to be lower and the water activity was less. Although the acidity remained stable and was not differentiable between the two treatments; the different evaporative conditions had a profound effect on other physiochemical properties, especially the external appearance of the final product. The visual appearance was determined by the Hunter indices (L, a, and b) and delta E (overall color change). As the operating temperature increased, the delta E in both treatments increased. The sample in the vacuum treatment became darker (lower L-value) and more intense in yellow color (higher b-value). This was hypothesized to be the result of product condensation due to moisture loss. The a-value decreased as the operating temperature increased and there was no significant difference between the two treatments. The viscosity of the final product had a unique profile regarding the operating temperature variation. It appeared to be more viscous than the fresh sample at low temperature. For the higher temperature setting, the viscosity decreased as the temperature increased. Enzymatic and non-enzymatic chemical reactions might be responsible for the alteration of the flow characteristics of dehydrated sample rather than the sole effect of moisture reduction.

Production and evaluation of mineral and nutrient contents, chemical composition, and sensory properties of ice creams fortified with laboratory-prepared peach fibre

“…It was found by monitoring the samples in the present study that the flour obtained from peach peel had a darker colour than that produced from pulp. Because of the possible existence of some browning contributor enzymes, such as polyphenol oxidase, and the occurrence of the Maillard reaction (31), a significant colour change was observed during the peel drying process in the present study, from which dark brown powder was produced from the peel. The L* , a* , and b* values were found to be 76, 5.5, and 29.39 in peach pulp flour, and 56, 12.2, and 34 in peach peel flour, respectively (7), and these results are in agreement with the results of the present study.…”

Comparing physicochemical properties of banana pulp and peel flours prepared from green and ripe fruits

“…Major change in colour took place during drying of the peel that yielded dark brown powder, particularly in the ripe samples. As banana peel contains glucose, fructose and protein (Emaga et al, 2007), an extend of the Maillard reaction could had occurred, while certain enzymes such as polyphenol oxidase may be present in banana peel that could contribute a certain degree of enzymatic browning (Thipayarat, 2007). This later explanation seems acceptable since the enzymatic browning of banana is well known problem.…”

“…Inconsistency in b ⁄ value might have been attributed to the excessive browning occurring in the peel during drying, and to some extend the presence of dark spots scattering about the flour and interfere with colour analyses. No study could be found on the effect of drying on banana peel, but quality of banana paste as influenced by vacuum dehydration has been studied by Thipayarat (2007). It was found that banana paste dehydrated with vacuum dehydration had darker colour (lower L value) and more intense yellow colour (higher b value) that was hypothesised to be due to condensation and to moisture loss, enzymatic and non-enzymatic browning (Thipayarat, 2007).…”

Functionality and Physicochemical Properties of the Chirimoya Flour (Annona Cherimola Miller) Cv. Cumbe

“…This comparative color advantage is remarkable, given that the HCh had a high content of soluble solids and was dehydrated at 50 °C, while that obtained by (Alkarkhi, Bin Ramli, Yong, & Easa, 2011) had a lower content of soluble solids and was dehydrated at 60 °C. Therefore, it is likely that the use of antioxidant has not been effective, favoring the Maillard reaction and the high enzymatic activity of the polyphenol oxidase present in the banana that could contribute to a certain degree of enzymatic browning (Thipayarat, 2007). Enzymatic browning of bananas is a well-known problem, although also in cherimoya, the use of sodium bisulfite as an antioxidant result being effective for this type of Annona.…”