Influence of probiotics, prebiotics, synbiotics and bioactive phytochemicals on the formulation of functional yogurt

The new concept of functional foods has led to the varieties in the production of foods that deliver not only basic nutrition, but can also warrant good health and longevity. Yogurt has become one of the prevalent choices and considered as a healthy food since it provides excellent sources of essential nutrients. As the popularity of yogurt continues to grow, manufacturers and scientists continuously investigate the value adding ingredients such as probiotics, prebiotics and different kinds of plant extracts to produce functional yogurt comprising extra beneficial properties than the conventional yogurt. This review summarises the current knowledge on functional yogurt, applications and roles of probiotic, prebiotic and synbiotic in yogurt as well as the effects of phytochemicals added in innovative yogurt products. Their important properties were focused based on significance influences on quality and sensory attributes of yogurt products and associated health aspects

Phytochemicals, antioxidant and antimicrobial properties of Senna alata and Senna tora leaf extracts against bacterial strains causing skin infections

A study was carried out to screen for phytochemical constituents and assess the antioxidant and antimicrobial activities of Senna alata and Senna tora leaf extracts. The leaves were first dried at room temperature and 50°C in an oven prior to solvent extraction using ethanol and methanol. The in-vitro qualitative assays showed that both S. alata and S. tora leaf extracts contained bioactive and secondary metabolites components such as tannins, steroids, saponin, terpenoids, glycosides, flavonoids and phenols. The antioxidant activity and capacity test were carried out by conducting free radical of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and Ferric reduction antioxidant plasma (FRAP) assays. Both assays showed S. tora leaf extract has higher antioxidant capacity than S. alata leaf extract. The efficacy of these leaf extracts were tested against skin pathogens through agar well diffusion method. S. alata extract showed an inhibition zone (1.15 –1.59 mm) against Pseudomonas aeruginosa while S. tora extracts exhibited a strong antimicrobial activity against S. epidermidis (inhibition zone of 12 –16.94 mm) followed by P. aeruginosa (inhibition zone of 1 –1.59 mm). Nonetheless, no inhibition zone was observed for S. aureus by both leaf extracts. The phytochemicals and antioxidant constituents as well as inhibitory potential on skin pathogens possessed by S. alata and S. tora leave highlighted their potential utilization in the development of natural drugs or cosmetics to treat skin related diseases or infections

Functional properties and characterization of yogurt fortified with Synsepalum dulcificum (Schumach. & Thonn.) Daniell and microencapsulated Lactococcus lactis Gh1

Nowadays, functional food market is dominated by dairy based probiotic products mainly yogurt. The nutritional values of yogurt can be further enhanced by the inclusion of Synsepalum dulcificum (Schumach. & Thonn.) Daniell extract and the addition of locally isolated probiotic Lactococcus lactis Gh1. S. dulcificum is a plant that possesses unique characteristics that can be used as a healthy food additive which acts as taste modifier besides providing antioxidant and anti-diabetic effects. The screening results of seed, leaf and pulp of S. dulcificum showed that pulp extracts contained significantly (P<0.05) higher antioxidant (85.69 ± 0.004) and phenolic content (15.93 ± 0.002 µg GAE Equiv. / g sample) than the other plant parts. More interestingly, S. dulcificum pulp also has stronger anti-diabetic properties than the standard drug, acarbose and hence it was chosen to be incorporated into yogurt. L. lactis Gh1 was encapsulated via extrusion (with alginate-starch coating agent) and spray drying (with gum Arabic and S.dulcificum pulp) methods to increase the cells viability. A total of seven different yogurts (C.plain (plain yogurt), C.pulp (contained pulp extract), F.plain (contained free cell L. lactis Gh1), F.pulp (contained free cell L. lactis Gh1 and pulp extract), B.plain (contained alginate-starch encapsulated L. lactis Gh1), B.pulp (contained pulp extract and alginate-starch encapsulated L. lactis Gh1), S.dry (contained spray dried L. lactis Gh1 coated with gum Arabic and pulp) were formulated. The yogurts were fermented at 42°C until pH 4.5 prior to storage at 4°C for 21 days. All the yogurts fortified with pulp extract showed a faster rate of pH reduction (~3 hours) than the plain yogurt (6 hours). The total phenolic content (TPC) of all yogurts showed an increasing trend throughout the storage. The presence of S. dulcificum pulp extract elevated (P<0.05) the TPC in the yogurts whereas the antioxidant activity (DPPH assay) and inhibitory activity towards the key enzymes associated with diabetes (α-amylase and α-glucosidase) showed a gradual increase on the first 7 days but decreased afterward. In comparison, yogurts fortified with pulp extract showed a higher (P<0.05) antioxidant and anti-diabetic activity than the plain yogurt. The viability of L. lactis Gh1 in yogurt showed the highest survivability even on the last day (day 21) of refrigerated storage when it was being encapsulated in beads and according to the following order: B.plain (9.43 log CFU/mL)>B.pulp (9.04 log CFU/mL)> F.pulp (8.26 log CFU/mL) > S.dry (8.08 log CFU/mL)> F.plain (6.76 log CFU/mL). Meanwhile, the CFU/mL of the yogurt starter cultures, Streptococcus thermophilus and Lactobacillus dulbrueckii of all yogurts were drastically increased for the first week of storage especially for yogurts added with a non- microencapsulated L. lactis Gh1 (F.plain and F.pulp) but started to decrease after day 7. The flow behaviour of all yogurt samples had exhibited shear thinning behaviour with n<1. In general, the incorporation of S. dulcificum and microencapsulated L. lactis Gh1 had greatly enhanced the quality and potential benefits of the functional yogurt products

Microencapsulation of Lactococcus lactis Gh1 with gum Arabic and Synsepalum dulcificum via spray drying for potential inclusion in functional yogurt

There has been an explosion of probiotic incorporated based product. However, many reports indicated that most of the probiotics have failed to survive in high quantity, which has limited their effectiveness in most functional foods. Thus, to overcome this problem, microencapsulation is considered to be a promising process. In this study, Lactococcus lactis Gh1 was encapsulated via spray-drying with gum Arabic together with Synsepalum dulcificum or commonly known as miracle fruit. It was observed that after spray-drying, high viability (~109 CFU/mL) powders containing L. lactis in combination with S. dulcificum were developed, which was then formulated into yogurt. The tolerance of encapsulated bacterial cells in simulated gastric juice at pH 1.5 was tested in an in-vitro model and the result showed that after 2 h, cell viability remained high at 1.11 × 106 CFU/mL. Incubation of encapsulated cells in the presence of 0.6% (w/v) bile salts showed it was able to survive (~104 CFU/mL) after 2 h. Microencapsulated L. lactis retained a higher viability, at ~107 CFU/mL, when incorporated into yogurt compared to non-microencapsulated cells ~105 CFU/mL. The fortification of microencapsulated and non-microencapsulated L. lactis in yogurts influenced the viable cell counts of yogurt starter cultures, Lactobacillus delbrueckii subs. bulgaricus and Streptococcus thermophilus

Strategies for introducing titania onto mesostructured silica nanoparticles targeting enhanced photocatalytic activity of visible-light-responsive Ti-MSN catalysts

Titanium-mesostructured silica nanoparticles (Ti-MSN) catalysts which are excellent photocatalytic materials for the environment were prepared by supporting mesostructured silica nanoparticles (MSNs) with titanium species synthesized by three different approaches: microwave and in situ and ex situ electrochemical methods, denoted as Ti-MSN-M, Ti-MSN-I, and Ti-MSN-E, respectively. The physicochemical properties of the catalysts were investigated via XRD, 29Si NMR, N2 adsorption-desorption, FTIR, ESR, and UV-DRS analyses. Characterization results revealed that the introduction of mesoporous titania nanoparticles (MTNs) prepared by the microwave method onto MSNs (Ti-MSN-M) did not significantly affect the silica framework. However, the silica network in the Ti-MSN-I and Ti-MSN-E was rather disrupted, particularly for the former catalyst, due to the desilication accompanied by isomorphous substitution of Ti in the MSN framework to form Si[sbnd]O[sbnd]Ti bonds. Ti was also found to be exchanged with the terminal hydroxyl groups of all catalysts to form the Si[sbnd]O[sbnd]Ti bonds. The addition of Ti species onto MSNs also increased the number of oxygen vacancies (Vo) and metal defect sites. Photocatalytic testing on the decolorization of Congo red (CR) resulted in the following order: Ti-MSN-I (94%) > Ti-MSN-M (90%) > Ti-MSN-E (34%). The Vo and metal defect sites were responsible in lowering the band gap of catalysts and decreasing the electron–hole recombination, while the great numbers of Si[sbnd]O[sbnd]Ti bonds as well as large surface area and pore volume increased the active sites and offered a good surface contact with light to enhance the activity of catalysts. A kinetic study demonstrated that the photodegradation followed the pseudo-first-order Langmuir-Hinshelwood model. Ti-MSN-I and Ti-MSN-M maintained their activities for up to five runs without serious catalyst deactivation, indicating their potential for the degradation of dye in wastewater. Mineralization measurements of CR by TOC and BOD5 analyses after 3 h of contact time were 85.7% and 87.6% using Ti-MSN-M, while 83.7% and 80.3% using Ti-MSN-I, respectively. Optimization by response surface methodology showed that the catalyst dosage, pH, and TiO2 loading were the significant factors in the decolorization of CR. This study demonstrated that these two green technologies; electrochemical and MW have a great potential to be used in synthesis of various advanced materials for greener and more sustainable processes