Quality Changes and Lactobacillus casei 01 Survivability in Milk and Maoberry Mousse Products Supplemented with Inulin during Refrigerated Storage

Abstract

Background and Objectives : Mousse is a light and airy dessert made by incorporating air into a mixture of whipped cream, egg whites, or gelatin, creating a smooth and fluffy texture. It can be sweet or savory, with popular variations including chocolate and fruits. Maoberry or Mao-Luang (Antidesma bunius) is a tropical fruit rich in bioactive compounds, including antioxidants, flavonoids, and phenolic acids. Scientifically, it has been shown to exhibit anti-inflammatory, antimicrobial, and cardioprotective properties. The fruit supports digestive health, regulates blood sugar levels, and enhances immune function due to its high vitamin and mineral content. Inulin is a natural prebiotic fiber found in plants like chicory root, garlic, and onions, scientifically recognized for promoting gut health by stimulating beneficial bacteria growth. It aids digestion, improves bowel regularity, and enhances nutrient absorption. Inulin also supports metabolic health by regulating blood sugar levels. Additionally, its ability to increase satiety helps with weight management and appetite control. Probiotics are live microorganisms, primarily bacteria and yeasts, which provide health benefits when consumed in adequate amounts. They mainly belong to genera Lactobacillus and Bifidobacterium. Probiotics offer numerous health benefits by promoting gut health, enhancing digestion, and strengthening the immune system. They play a vital role in preventing gastrointestinal disorders and aiding in weight management. Regular consumption of probiotics through foods or beverages can significantly enhance overall well-being. Thus, this research aimed to investigate the changes in qualities and the survival rate of probiotic Lactobacillus casei 01 in milk and maoberry mousses supplemented with inulin during refrigerated storage at 4ºC for 12 days.

Methodology :  Probiotic-mousse formulas, including milk mousse, milk mousse supplemented with inulin, maoberry mousse, and maoberry mousse supplemented with inulin, were produced and were then refrigerated stored at 4ºC for 12 days. The samples were taken every 3 days for quality assessments in various aspects, viz. physical (color parameters and firmness), chemical (total soluble solids, pH, and total titratable acidity), and microbiological qualities. Amounts of bioactive compounds (ascorbic acid, total anthocyanins, and total polyphenolic compounds) and antioxidant activity (DPPH and FRAP assays) were investigated. The survival rates of probiotic L. casei 01 in the samples were also monitored.

Main Results : From the experimental results, it was found that anthocyanins, which were the main pigments found in maoberry, affected the color values (L, a*, and b*) of the mousse samples. However, the addition of inulin did not affect the color values of the samples. It was also found that maoberry mousses had lower firmness and pH values than the milk mousses. The addition of inulin did not affect the texture and pH values of the mousses. Additionally, it was found that maoberry mousses had higher levels of ascorbic acid, total anthocyanins, and total polyphenolic compounds, as well as higher antioxidant activity (DPPH and FRAP assays), than the milk mousses. During storage the samples in a refrigerator at 4ºC for 12 days, it was found that the addition of maoberry pulp had a greater effect on color changes than the addition of inulin. Color changes in maoberry mousses were primarily due to the degradation of anthocyanins. The firmness of the samples increased from the first day of storage, especially in milk mousse supplemented with inulin. It was also found that total soluble solids in all samples remained unchanged, but pH value slightly decreased. Amounts of ascorbic acid, total anthocyanins, and total polyphenolic compounds, as well as antioxidant activity, decreased during the refrigerated storage. However, maoberry mousses maintained higher levels of bioactive compounds and antioxidant activity compared to the other. This research also highlighted the role of inulin in increasing the survival rate of probiotic L. casei 01 during storage. The numbers of L. casei 01 in mousses supplemented with inulin remained above 6 log CFU/g after 12 days of storage. In contrast, the numbers of L. casei 01 in mousses without inulin addition decreased to below 6 log CFU/g within the storage period. It was evident that the numbers of L. casei 01 in both milk and maoberry mousses supplemented with inulin met the probiotic standard, which should have a count of at least 6 - 7 log CFU/g in food before consumption. Furthermore, the analysis of total plate counts, yeasts-molds, coliforms, and various pathogenic microorganisms, viz. Escherichia coli, Listeria monocytogenes, Salmonella, and Staphylococcus aureus, in all samples during storage, found that the numbers of all microbial groups remained below the dairy product standards.

Conclusions : Overall, this research found that t ingredients used in the production of mousses affected various quality aspects of the products during refrigerated storage (4ºC). Maoberry significantly impacted the color parameters, firmness, and pH, as well as the amounts of bioactive compounds and antioxidant capacity of the samples. Inulin affected the texture and helped increase the survival rate of L. casei 01. After 12 days of storage, the numbers of various indicator microorganisms remained within the standards for dairy products, ensuring consumer safety.