Encapsulation of lactase in Ca(II)-alginate beads: Effect of stabilizers and drying methods

Abstract

The purpose of the present work was to analyze the effect of trehalose, arabic and guar gums on the preservation of β-galactosidase activity in freeze-dried and vacuum dried Ca(II)-alginate beads. Freezing process was also studied as a first step of freeze-drying. Trehalose was critical for β-galactosidase conservation, and guar gum as a second excipient showed the highest conservation effect (close to 95%). Systems with T values ~40°C which were stables at ambient temperature were obtained, being trehalose the main responsible of the formation of an amorphous matrix. Vacuum dried beads showed smaller size (with Feret's diameter below 1.08±0.09mm), higher circularity (reaching 0.78±0.06) and large cracks in their surface than freeze-dried beads, which were more spongy and voluminous. Ice crystallization of the beads revealed that the crystallization of Ca(II)-alginate system follows the Avrami kinetics of nucleation and growth. Particularly, Ca(II)-alginate showed an Avrami index of 2.03±0.07, which means that crystal growing is bidimensional. Neither the addition of trehalose nor gums affected the dimension of the ice growing or its rate. These results open an opportunity in the development of new lactic products able to be consumed by lactose intolerance people.

Pink grapefruit lycopene encapsulated in alginate‐based beads: stability towards freezing and drying

“…Traffano‐Schiffo et al . () observed that FD produced lower WC values than VD in similar Ca(II)‐alginate beads containing trehalose and gums; instead, Santagapita et al . (, ) observed higher water content in FD systems for Ca(II)‐alginate beads containing trehalose and P or Ch containing beads.…”

“…In wet beads subjected to freezing, the crystallisation observed until reaching the first plateau corresponds to both water and lipids, with higher proportion of crystallised water at −20 °C (54%, with 46% corresponding to lipids) than at −30 °C (31% water, 69% lipid). Assuming the proportion of crystallised lipid is similar in all formulations, each bead system showed differences in the amount of crystallised water, in accordance to Traffano‐Schiffo et al ., , . The presence of trehalose reduced significantly the obtained values, mainly due to the formation of an amorphous matrix retaining a greater mass of water that is kinetically inhibited/delayed to crystallise (Traffano‐Schiffo et al ., ).…”

“…The kinetics of crystallisation was modelled by applying Avrami equation (Traffano‐Schiffo et al ., ), obtaining two relevant parameters: n (or Avrami index) which is related to the mechanism of nucleation and crystal growth, and k , which is the constant isothermal crystallisation. This equation has often been used to describe the overall isothermal crystallisation rate (Traffano‐Schiffo et al ., ). n values were 1.72 and 1.43 (both ±0.03) for wet and freeze‐dried A‐T beads frozen at −70 °C, being similar for other analysed beads (data not shown), with k values around 0.36 and 0.40 (both ±0.01), respectively.…”

“…However, some disadvantages are associated with this carrier, including high biomolecule leakage, low mechanical strength, large pore size and low cryo‐ and dehydro‐capacities (Santagapita et al ., ; Traffano‐Schiffo et al ., ), revealing the need to add other matrix components. In a previous work, it was shown that alginate beads with the addition of sugars and biopolymers were capable of enhancing the stability towards isomerisation as well as control the release of an encapsulated free‐solvent extract of lycopene (Aguirre Calvo & Santagapita, ; Aguirre Calvo et al ., ) and enzymes (Traffano‐Schiffo et al ., , , ). Lycopene is a naturally occurring red carotenoid pigment present in tomatoes, watermelon, pink grapefruit, pink guava and papaya (Sinha & Dua, ) with health benefits associated with lower risk of some degenerative diseases that may play a specific role in preventing prostate cancer and cardiovascular disease (Costa‐Rodrigues et al ., ).…”

In Situ Random Microseeding and Streak Seeding Used for Growth of Crystals of Cold-Adapted β-d-Galactosidases: Crystal Structure of βDG from Arthrobacter sp. 32cB

“…They are especially relevant in the dairy industry due to their ability to catalyze the hydrolysis of lactose, a natural substrate. Enzymatically hydrolyzed lactose, especially in milk, whey, or whey derivatives, is broadly used due to its higher sweetness, which ameliorates product taste, and to application in specialized food production, for people with lactose malabsorption [1][2][3]. Administration of products with depleted levels of lactose and other digestible oligosaccharides, disaccharides, monosaccharides, and polyols instead of common food is beneficial in the prevention of irritable bowel syndrome (IBS) [4][5][6][7][8][9].…”