Production and characterization of pineapple-mint juice by spray drying

Highlights

• Spray drying conditions were evaluated in pineapple-mint juice drying.

• Pineapple-mint juice can be dried in spray drying without maltodextrin.

• Mint can develop a similar role as carrier agents in spray drying process.

Abstract

This work studied pineapple-mint juice drying by spray drying. The effect of 0, 3, and 15% of maltodextrin addition in the solution fed in the spray dryer was evaluated. The results showed that it is possible to dry pineapple-mint juice without a carrier agent. A two-level full factorial design of experiments was applied to quantify the effect of spray drying conditions (including the addition of 3% maltodextrin on pineapple-mint juice) on powder physicochemical properties. The estimated effects demonstrated that all variables have affected responses (except powder solubility). Interested in investigating pineapple-mint drying without maltodextrin, the two-level factorial design was further expanded to a central composite design, and additional experiments were realized, resulting in preservation of the natural green color of pineapple-mint juice, and a yield of 35%. The results suggest that mint may help in pineapple-mint juice drying.

Introduction

According to estimates of Food and Agriculture Organization of the United Nations, the world production of pineapple was approximately 28.3 million tonnes in 2018, which puts pineapple in second place in the global tropical fruit production ranking. Brazil is the second producer in the world and has significant domestic consumption of pineapples [1]. The fruit is much appreciated and can be consumed in the natural state or as an ingredient in beverages such as juice, soda, sweet canned, etc. [2]. Green mint (Mentha spicata L.) is known to have several biological uses, mainly for medicinal purposes, such as stomach and intestinal analgesic, stimulant of cardiac functions and capacity to improve memory [3]. It also contains antimicrobial [4] and antioxidants [5] compounds, being highly beneficial to health [6]. Besides, green mint is a rich source of menthol, which enables its industrial application in various products, such as flavorings of food and drinks [7]. In other cases, it is used in association with other products, like pineapple-mint juice.

Although it has several health benefits, the consumption of fruits such as pineapples has been decreasing due to the new habits of consumers, who are increasingly opting for convenient and non-perishable foods. Therefore, it is necessary to develop processes and products that meet consumers' demands. One of the methods used by industries that help to alleviate this type of problem is drying, as it generates convenient products for consumers while extending the shelf life of perishable foods. Spray drying allows the production of several powdered products, however the use of carrier agents is generally necessary when fruit juices are being drying, which could be a disadvantage in some cases [8].

Maltodextrin [(C₆H₁₀O₅)_n.H₂O] is one of the most used carrier agents in the drying of products in spray dryers. One of its advantages is the reduction of the hygroscopicity of powders containing higher concentrations of the agent [9]. Maltodextrin also contributes to the rehydration capacity of dry products, due to the reduced stickiness of the particles, which facilitates their solubility in water since the particles' higher contact surface with water will be more extensive [10]. However, the addition of maltodextrin has a disadvantage, once it can change product's nutritional profile due to the increase in the proportion of carbohydrates.

Many studies are available in the literature about the use of the spray dryer to obtain powdered fruit juice, such as watermelon [11], juçara [12], tamarind [13], mango [14,15], blueberry [16], pomegranate [17,18], acerola [19], tomato [20] and noni [21], with different carrier agents and in different concentrations. However, there are few studies about spray dried pineapple-mint juice, even with and without additives.

Therefore, the objective of this work was to investigate the influence of spray drying conditions on the pineapple-mint powders' physicochemical characteristics. The influence of drying with and without maltodextrin on the scanning electron microscopy and sorption and moisture isotherms of the powders obtained in the spray drying process was also investigated.