Shelf-life of reduced-fat white chocolate fillings using iota-carrageenan

Abstract

The conservation of traditional chocolate fillings can present some hurdles due to the use of perishable raw matters, physical changes during processing and to the influence of external factors, which tends to shorten shelf-life of traditional filled pralinés to only 3-4 months. The aim of this study was to evaluate the influence of the concentration of iota-carrageenan on chemical, rheological, image analysis and microbial properties of reduced-fat white chocolate fillings during storage time. Two batches of reduced-fat filling were produced using white chocolate, commercial grade sugar, skimmed milk, inverted sugar and iota-carrageenan (at 0.5 % w/w and 1.0 % w/w concentration) and stored at 4 ºC during 12 months. A control batch with no hydrocolloid was also produced. The results presented a decrease in pH, aw and moisture during storage time. The rheological characterization concluded that all formulations presented a shearthinning behaviour and both flow index (n) and consistency (K) were correlated with iota-carrageenan concentration and with storage time. The concentration of iota-carrageenan did not influence the digital image analysis of chocolate fillings, but a shift was observed during storage time, especially at the end. The microbial analysis showed a positive correlation to storage time in the formulation using 1.0 % iota-carrageenan, nevertheless all results were quite acceptable and within the recommended safety values.

Effect of High Pressure on the Properties of Chocolate Fillings during Long-Term Storage

“…The initial pH value was 5.20 ± 0.01 ( Table 2 ), slightly below previous results on comparable products [ 6 ], due to the acidic profile of the dark chocolate used in the present study. According to the literature, pH values around 5.5 may hinder the growth of bacteria and fungi, however, its viability may not be affected [ 20 ].…”

“…At the end of storage time, no significant changes were observed ( p > 0.01), regardless of the storage temperature or pressure. The initial values of aw were, approximately, 0.92 ± 0.01 ( Table 2 ) higher than other authors [ 6 , 10 ] as a consequence of the higher moisture content [ 4 ]. At the end of storage time, no significant changes were observed ( p > 0.01).…”

“…At the end of storage time, the highest G′ 1Hz values were observed in HPP condition 400/10. Previous studies on milk chocolate [ 25 ] and filled chocolates [ 6 ] also reported a harder texture of staled chocolates than fresh samples, possibly as a result of a change in the crystallinity of the cocoa butter with time [ 25 ]. Additionally, some studies about the impact of HPP on the stability of emulsions have concluded that pressure and time of HPP have the capacity to control the lipid crystallization process and change the crystal structure in emulsions [ 26 ], which may affect the stability of fat networking created in the ganache [ 3 ].…”

“…However, so much water together with a high content of sugar and proteins creates a good culture media for the development of numerous microorganisms such as fungi, yeasts and pathogenic bacteria such as Salmonella and Listeria spp. [ 4 ], with this being the main reason for the reduction in shelf life to just 3–4 months [ 6 ]. Additionally, the high amount of nutrients, especially fat, protects these microorganisms from treatments used in conservation processes, thus making chocolate a matrix in which microorganisms are also protected when they cross the digestive tract, resisting acidity in the stomach.…”

“…[ 7 ]. This situation represents a challenge to the chocolate industry, where the most followed strategies to extend shelf life include the thermal treatment of cream [ 6 ], reduction in water activity or pH, use of ethanol, use of preservatives [ 8 ] or creating a balance between the humidity of the ganache and the environment [ 4 ]. Additionally, refrigeration is an important solution for maintaining food safety high standards and food quality due to the impact on microbiological growth slowdown (e.g., mesophilic growth), physiological processes (e.g., ripening), biochemical reactions (e.g., lipid oxidation) or physical changes (e.g., desiccation).…”