Abstract

In food processing, falling film evaporators are commonly used and their energy consumption is a significant operating cost for the production of juice concentrate. This cost is influenced not only by the evaporator design but also by the method of operation, particularly the fouling of the heat exchanger walls formed during the operation of the evaporator on the inner surface of the tubes from the juice side. These deposits are a significant component of the total wall thermal resistance, thus hindering evaporation. This issue results in a production decrease and requires evaporator cleaning. The publication presents an analysis of the calculation methods of fouling formation and their thermal resistance based on a literature review on evaporators for the production of sugar and milk. The obtained results were then processed by adjusting the coefficients to the experimental results obtained during the actual production of fruit juice concentrate. The decrease in actual evaporator efficiency was used to experimentally verify the theoretical calculations. This analysis resulted in a final simple formula for the estimation of the fouling influence on evaporator performance under industrial conditions. Simulations have shown that a sharp drop in evaporator efficiency may occur with insufficient recirculation or prolonged operation without cleaning. In this case, the amount of sediment can increase and cause a change in the boiling character and thus a rapid decrease in evaporation.

Abstract

The present study aimed to develop a mixed smoothie drink using the solid albumen of the green coconut in its composition. Smoothie formulations were prepared following an experimental design, setting the solid albumen concentration at 20% and varying the contents of the acerola (Barbados Cherry), pineapple, and coconut water pulps, which corresponded to 80% of the total mass of the product. Response parameters evaluated were vitamin C content, antioxidant capacity, and overall sensory acceptance. Ten formulations were evaluated. The ones that contained higher concentrations of acerola pulp had higher values of bioactive compounds but were not the most sensorially accepted. By means of the desirability function, a final formulation consisted of 52.8% of pineapple, 27.2% of acerola, and 20.0% of solid albumen of green coconut. This new formulation was well accepted, with a grade (score) 7 (“good”). It represents a good nutritional contribution and a source of vitamin C which can contribute to add value to a co-product of the beverage industry.

Effect of sugar reduction on flavour release and sensory perception in an orange juice soft drink model

Abstract

To examine the effect of sugar reduction on the sensory perception of sweetened beverages, an orange juice soft drink model flavoured with seven characteristic compounds (hexanal, decanal, linalool, ethyl butanoate, α-pinene, β-myrcene and (Z)-3-hexen-1-ol) was developed. Five samples were prepared with relevant sugar contents (5.2, 8.2, 9.7, 11.2 and 14.2 °Brix). Using retronasal quantitative descriptive analysis (QDA), nine attributes were found to differ significantly (p < 0.05) with sugar content. When the samples were evaluated orthonasally, only the attribute “overripe orange” significantly decreased (p < 0.05) with reduction of sugar content. Headspace solid-phase microextraction with gas chromatography–mass spectrometry showed that as sugar concentration decreased, the headspace concentration of six of the volatile compounds decreased, whilst ethyl butanoate remained constant. Principal component analysis revealed that the total release of the flavour compounds was highly correlated with the perceived intensity of the orthonasal attribute “overripe orange”.

UV-C light processing of Cantaloupe melon juice: Evaluation of the impact on microbiological, and some quality characteristics, during refrigerated storage

Abstract

UV-C light is a non-thermal technology with potential application in food industries. The objective was to assess UV-C radiation effect (13.44 W/m²) on microbiological decontamination and some quality characteristics of Cantaloupe melon juice, during refrigerated storage.

Juice was inoculated with Listeria innocua (non-pathogenic surrogate of L. monocytogenes) and Alicyclobacillus acidoterrestris spores (spoilage indicators) used as indicators of the UV-C treatment efficacy. Total mesophylls and yeasts and molds were also enumerated. Results demonstrated that 5 min of exposure allowed 3.7 ± 0.3 log₁₀ cycles reduction of L. innocua, while for A. acidoterrestris, 20 min were required to decrease 4.7 ± 0.1 log₁₀ cycles.

At the end of refrigerated storage for 13 days, UV-C treated juices retained color, total phenolics content and antioxidant activity, and yeast and molds did not grow.

Since UV-C process was effective on microbial inactivation and allowed juice quality maintenance, it can be considered as a promising alternative to thermal pasteurization.