Effect of encapsulation on the stability and survivability of Enterococcus faecium in a non-dairy probiotic beverage

Enhancing storage and gastroprotective viability of Lactiplantibacillus plantarum encapsulated by sodium caseinate-inulin-soy protein isolates composites carried within carboxymethyl cellulose hydrogel

Probiotics are subjected to various edible coatings, especially proteins and polysaccharides, which serve as the predominant wall materials, with ultrasound, a sustainable green technology. Herein, sodium caseinate, inulin, and soy protein isolate composites were produced using multi-frequency ultrasound and utilized to encapsulateLactiplantibacillus plantarumto enhance its storage, thermal, and gastrointestinal viability. The physicochemical analyses revealed that the composites with 5 % soy protein isolate treated with ultrasound at 50 kHz exhibited enough repulsion forces to maintain stability, pH resistance, and the ability to encapsulate larger particles and possessed the highest encapsulation efficiency (95.95 %). The structural analyses showed changes in the composite structure at CC, CH, CO, and amino acid residual levels. Rheology, texture, and water-holding capacity demonstrated the production of soft hydrogels with mild chewing and gummy properties, carried the microcapsules without coagulation or sedimentation. Moreover, the viability attributes ofL. plantarumevinced superior encapsulation, protecting them for at least eight weeks and against heat (63 °C), reactive oxidative species (H2O2), and GI conditions.

Viability of Free and Alginate-Carrageenan Gum Coated Lactobacillus acidophilus and Lacticaseibacillus casei in Functional Cottage Cheese

The survivability of encapsulated and nonencapsulated probiotics consisting of Lactobacillus acidophilus and Lacticaseibacillus casei and the nutritional, physicochemical, and sensorial features of cottage cheese were investigated under refrigeration storage at 4 °C for 28 days. Microbeads of L. acidophilus and L. casei were developed using 2% sodium alginate, 1.5% sodium alginate and 0.5% carrageenan, and 1% sodium alginate and 1% carrageenan using an encapsulation technique to assess the probiotic viability in cottage cheese under different gastrointestinal conditions (SGF (simulated gastric juice), SIF (simulated intestinal fluid)), and bile salt) and storage conditions. Scanning electron microscopy (SEM) elucidated the stable structure of microbeads, Fourier transform infrared spectroscopy (FTIR) confirmed the presence probiotics in the microcapsules, and X-ray diffraction (XRD) demonstrated the amorphous state of microbeads. Furthermore, the highest encapsulation efficiency was observed for alginate 1% and carrageenan 1% microbeads (T3), i.e., 95%. Likewise, viability was recorded in T3 against SGF, SIF, and bile salt solution, i.e., 8.5, 8.8, and 8.9 log CFU/g at 80 min of exposure, compared to the control. The results of pH showed a significant (p < 0.05) decline that ultimately increased the titratable acidity. Nutritional analysis of cottage cheese revealed the highest levels of ash, protein, and total solids in T3, exhibiting mean values of 3.2, 22, and 43.2 g/100 g, respectively, after 28 days of storage. The sensory evaluation of cottage cheese demonstrated better color, flavor, and textural attributes in T3. Conclusively, synergistic addition of L. acidophilus and L. casei encapsulated with alginate-carrageenan gums was found to be more effective in improving the viability of probiotics in cottage cheese than noncapsulated cells while carrying better magnitudes of ash and protein, lower acidity, and pleasant taste.

Protein-polysaccharide based double network microbeads improves stability of Bifidobacterium infantis ATCC 15697 in a gastro-Intestinal tract model (TIM-1)

Microencapsulation of probiotics is a main technique employed to improve cell survival in gastrointestinal tract (GIT). The present study investigated the impact of utilizing proteins i.e. Whey Protein Isolates (WPI), Pea Protein Isolates (PPI) or (WPI + PPI) complex based microbeads as encapsulating agents on the encapsulation efficiency (EE), diameter, morphology along with the survival and viability of Bifidobacterium infantis ATCC 15697. Results revealed that WPI + PPI combination had the highest EE% of the probiotics up to 94.09 % and the smoothest surface with less visible holes. WPI based beads revealed lower EE% and smaller size than PPI based ones. In addition, WPI based beads showed rough surface with visible signs of cracks, while PPI beads showed dense surfaces with pores and depressions. In contrast, the combination of the two proteins resulted in compact and smooth beads with less visible pores/wrinkles. The survival in gastrointestinal tract (GIT) was observed through TNO in-vitro gastrointestinal model (TIM-1) and results illustrated that all microbeads shrank in gastric phase while swelled in intestinal phase. In addition, in-vitro survival rate of free cells was very low in gastric phase (18.2 %) and intestinal phase (27.5 %). The free cells lost their viability after 28 days of storage (2.66 CFU/mL) with a maximum log reduction of 6.76, while all the encapsulated probiotic showed more than 106-7 log CFU/g viable cell. It was concluded that encapsulation improved the viability of probiotics in GIT and utilization of WPI + PPI in combination provided better protection to probiotics.

Stability and Survivability of Alginate Gum-Coated Lactobacillus rhamnosus GG in Simulated Gastrointestinal Conditions and Probiotic Juice Development

Survivability of probiotics is severely affected by harsh gastrointestinal conditions. In the present study, microbeads of Lactobacillus rhamnosus GG were formulated using alginate (1.5% w/v) and combination of alginate (1.5% w/v) with xanthan gum (0.5% w/v) through an emulsion technique to improve bacterial viability in low pH orange juice and in gastrointestinal conditions. The microbeads were tested for encapsulation efficiency, survivability in bile salt, SGF (simulated gastric juice), SIF (simulated intestinal fluid), and storage stability. Probiotic orange juice was formulated and tested for physicochemical parameters (pH, titratable acidity, and total sugars) and sensorial properties during storage. Gum-coated alginate microbeads (T3) showed higher encapsulation efficiency, i.e., 95.2% compared to alginate microbeads (T2), i.e., 86.85%. Similarly, T3 showed the highest resistance against bile salt (8.50 log CFU/g), SGF (7.95 log CFU/g), and SIF (8.0 log CFU/g) during 80 min exposure compared to T2 and free cells. The viability of gum-coated alginate beads (T3) remained above 107 CFU/g in gastrointestinal conditions and at the end of 21 days storage (8.3 log CFU/mL). All physicochemical parameters of probiotic juice were significantly ( $p\le 0.05$ ) decreased with respect to storage except acidity. In addition, minimal changes in physicochemical parameters were observed in T3 compared to other treatments. Treatment had no significant impact on the sensory characteristics of juice, but storage had a significant effect ( $p\le 0.05$ ) on the sensory characteristics of juice. The alginate gum microbeads improve the survivability of probiotics for targeted delivery. Hence, encapsulated probiotics can be used for functional beverage development to take advantage of their therapeutic benefits.

Prebiotic Functions of Konjac Root Powder in Chocolate Milk Enriched with Free and Encapsulated Lactic Acid Bacteria

This study investigated the prebiotic functions of Konjac root powder (KRP) when added to chocolate milk (ChM) enriched with 2% of free or microencapsulated lactic acid bacteria (FLAB or ELAB). The effects of different concentrations of KRP (0%, 2% and 4%) and refrigerated storage time on the physical, chemical and microbiological characteristics of this chocolate milk were examined. The results show that pH significantly declined (p < 0.05), while titratable acidity increased in all ChM samples with KRP and FLAB or ELAB during refrigerated storage. The pH values ranged from 6.0 ± 0.03 in samples enriched ELAB and 4% KRP to 6.33 ± 0.03 in ChM enriched with FLAB and 2% KRP. Viscosity of ChM was affected mainly by the added amounts of KRP and storage time. The largest viscosity (5500 cP) was observed in all samples containing 4% KPR on day zero and decreased significantly (p < 0.05) over storage time to reach 2800 cP in ChM samples containing 0% LAB and 4% KRP after 21 days of storage. Changes in LAB counts proved the initial hypothesis that KRP could act as prebiotics in the presence of LAB using chocolate milk as a carrier. The initial LAB counts in inoculated samples on day zero of refrigeration storage were not significantly different (p > 0.05) among all treatments. However, ChM enriched with 2% and 4% KRP and ELAB revealed significantly (p < 0.05) larger LAB counts (4.91 ± 0.78 and 5.0 ± 0.57 log CFU/mL, respectively) than the control (3.85 ± 0.55 log CFU/mL) after 21 days of storage.

Synbiotic microencapsulation of Enterococcus faecium Rp1: a potential probiotic isolated from ragi porridge with antiproliferative property against colon carcinoma cell line

Ragi porridge, commonly consumed in South India is made from finger millet and noiyee (broken rice), and it is one of the excellent sources for probiotic bacteria. In vitro assays provided the proof that the probiotic strains isolated from ragi porridge can survive during the intestinal passage. Also, it showed antioxidant activity and antagonistic activity against foodborne pathogens including Shigella flexineri, Staphylococcus aureus, Salmonella typhii and Escherichia coli. Enterococcus faecium Rp1 isolated from ragi porridge was susceptible to vancomycin and showed to cease the progression of HCT116 (colon carcinoma) cell line. Further, Enterococcus faecium was microencapsulated using sodium alginate and aloe vera gel as binding agents and onion extract as a source of prebiotic to perform symbiotic encapsulation. In short, this study concludes that the fermented Ragi porridge is a rich source of probiotics with anti-microbial, antioxidant and antiproliferative property hence can be suggested for improving gut microbiota.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05415-2.

Microencapsulation of Probiotics for Food Functionalization: An Update on Literature Reviews

Functional foods comprise the largest growing food category due to both consumer demands and health claims by manufacturers. Probiotics are considered one of the best choices for meeting these demands. Traditionally, the food vehicle for introducing probiotics to consumers was dairy products, and to expand the benefits of probiotics for a wider range of consumers, the need to use other food items was essential. To achieve this goal while maximising the benefits of probiotics, protection methods used during food processing were tackled. The microencapsulation of probiotics is a promising methodology for achieving this function. This review highlights the use of the microencapsulation of probiotics in order to functionalise food items that initially were not considered suitable for probiotication, such as baked products, or to increase their functionality such as dairy products. The co-microencapsulation of probiotics with other functional ingredients such polyphenol, prebiotics, or omega-3 is also highlighted.

A systematic review on chlorine tolerance among bacteria and standardization of their assessment protocol in wastewater

Though chlorine is a cost-effective disinfectant for water and wastewaters, the bacteria surviving after chlorination pose serious public health and environmental problems. This review critically assesses the mechanism of chlorine disinfection as described by various researchers; factors affecting chlorination efficacy; and the re-growth potential of microbial contaminations in treated wastewater post chlorination to arrive at meaningful doses for ensuring health safety. Literature analysis shows procedural inconsistencies in the assessment of chlorine tolerant bacteria, making it extremely difficult to compare the tolerance characteristics of different reported tolerant bacteria. A comparison of logarithmic reduction after chlorination and the concentration-time values for prominent pathogens led to the generation of a standard protocol for the assessment of chlorine tolerance. The factors that need to be critically monitored include applied chlorine doses, contact time, determination of chlorine demands of the medium, and the consideration of bacterial counts immediately after chlorination and in post chlorinated samples (regrowth). The protocol devised here appropriately assesses the chlorine-tolerant bacteria and urges the scientific community to report the regrowth characteristics as well. This would increase the confidence in data interpretation that can provide a better understanding of chlorine tolerance in bacteria and aid in formulating strategies for effective chlorination.

The Role of Microencapsulation in Food Application

Modern microencapsulation techniques are employed to protect active molecules or substances such as vitamins, pigments, antimicrobials, and flavorings, among others, from the environment. Microencapsulation offers advantages such as facilitating handling and control of the release and solubilization of active substances, thus offering a great area for food science and processing development. For instance, the development of functional food products, fat reduction, sensory improvement, preservation, and other areas may involve the use of microcapsules in various food matrices such as meat products, dairy products, cereals, and fruits, as well as in their derivatives, with good results. The versatility of applications arises from the diversity of techniques and materials used in the process of microencapsulation. The objective of this review is to report the state of the art in the application and evaluation of microcapsules in various food matrices, as a one-microcapsule-core system may offer different results according to the medium in which it is used. The inclusion of microcapsules produces functional products that include probiotics and prebiotics, as well as antioxidants, fatty acids, and minerals. Our main finding was that the microencapsulation of polyphenolic extracts, bacteriocins, and other natural antimicrobials from various sources that inhibit microbial growth could be used for food preservation. Finally, in terms of sensory aspects, microcapsules that mimic fat can function as fat replacers, reducing the textural changes in the product as well as ensuring flavor stability.