Probiotic properties of ice creams produced with dietary fibres from by‐products of the food industry

The objective of this study was to investigate the effects of adding dietary fibre‐rich by‐products to probiotic ice creams. For this purpose, fruit (grape, apricot, apple)‐ and grain (rice, corn, sunflower, barley)‐based by‐products were added to ice cream. The viability of Lactobacillus acidophilus (ATCC 4357D‐5) and Bifidobacterium animalis subsp. lactis (ATCC 27536) was determined with microbial analyses at 1, 15, 30 and 60 days of storage. In conclusion, it was shown that dietary fibre‐rich by‐products could be used in ice cream with improved survival of the probiotic strains without any adverse effects on the physicochemical, microbiological and sensory properties of the ice cream.     

Survival of Lactobacillus acidophilus LMGP‐21381 in probiotic ice cream and its influence on sensory acceptability

Probiotic ice cream was produced by incorporating Lactobacillus acidophilus LMGP‐21381 in a standard ice cream mix at initial population above 10⁷ cfu/g. The ice cream mix was inoculated with either freeze‐dried or activated cultures of L. acidophilus and a control treatment without probiotic was also prepared. The product was assessed for the survival of the probiotic strain during the freezing process and during 45 weeks of storage at ?15°C and ?25°C, and also for its sensory characteristics. The results showed that the freezing process caused a significant decrease in the viability of the freeze‐dried culture, but no significant change in the viable counts of L. acidophilus was observed during frozen storage. The sensory attributes of aroma, taste and texture obtained high scores in the sensory evaluation. It was demonstrated that incorporation of either activated or commercial freeze‐dried L. acidophilus culture resulted in a candidate food for the delivery of high levels of this probiotic strain to consumers.     

Effect of microencapsulation and resistant starch on the probiotic survival and sensory properties of synbiotic ice cream

Two types of synbiotic ice cream containing 1% of resistant starch with free and encapsulated Lactobacillus casei (Lc-01) and Bifidobacterium lactis (Bb-12) were manufactured. The survival of L. casei and B. lactis were monitored during the product’s storage for 180 days at −20 °C. The viable cell number of L. casei and B. lactis in the free state in prepared ice cream mixture was 5.1 × 10⁹ and 4.1 × 10⁹ CFU/mL at day one and after 180 days storage at −20 °C, these numbers were decreased to 4.2 × 10⁶ and 1.1 × 10⁷ CFU/mL, respectively. When we encapsulated the mentioned probiotic bacteria in calcium alginate beads, the probiotic survival raised at rate of 30% during the same period of storage at same temperature. In general, the results indicated that encapsulation can significantly increase the survival rate of probiotic bacteria in ice cream over an extended shelf-life. The addition of encapsulated probiotics had no significant effect on the sensory properties of non-fermented ice cream in which we used the resistant starch as prebiotic compound.     

Survival of free and encapsulated probiotic bacteria and their effect on the sensory properties of yoghurt

The survival and effect of free and calcium-induced alginate-starch encapsulated probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium lactis) on pH, exopolysaccharide production and influence on the sensory attributes of yogurt were studied over 7 weeks storage. Addition of probiotic bacteria (free or encapsulated) reduced acid development in yogurt during storage. Post-acidification in yogurt with encapsulated probiotic bacteria was slower compared to yogurt with free probiotic bacteria. More exopolysaccharides were observed in yogurts with probiotic cultures compared to those without probiotic cultures. The results showed that there was an increased survival of 2 and 1 log cell numbers of L. acidophilus and B. lactis, respectively due to protection of cells by microencapsulation. The addition of probiotic cultures either in the free or encapsulated states did not significantly affect appearance and colour, acidity, flavour and after taste of the yogurts over the storage period. There were, however, significant differences (P<0.05) in the texture (smoothness) of the yogurts. This study has shown that incorporation of free and encapsulated probiotic bacteria do not substantially alter the overall sensory characteristics of yogurts and microencapsulation helps to enhance the survival of probiotic bacteria in yogurts during storage.     

Calcium alginate‐resistant starch mixed gel improved the survival of Bifidobacterium animalis subsp. lactis Bb12 and Lactobacillus rhamnosus LBRE‐LSAS in yogurt and simulated gastrointestinal conditions

The aim of this study was to investigate the protective effect of microencapsulation in calcium alginate‐resistant starch mixed gel of a new human isolated strain of Lactobacillus rhamnosus LBRE‐LSAS compared with the probiotic strain of Bifidobacterium animalis subsp. lactis Bb12. Influence of microencapsulation was tested under deleterious digestive environment, when challenged to salivary α‐amylase, to simulated gastric fluid and to simulated intestinal fluid. Bacterial survival, post‐acidifying activity and exopolysaccharides (EPS) content in stored mix yogurt were assessed. Integrity of the beads was acceptable under α‐amylase levels largely higher than those found in human saliva. Under simulated gastrointestinal model, viable cell counts of encapsulated cells were significantly higher than those observed with free cells and remained at the recommended levels. Additionally, microencapsulation allowed an improved viability of bacteria and generated higher EPS amounts in mix yogurt stored at 4 °C. Our results indicate that calcium alginate‐resistant starch beads extend survival under digestive conditions and in yogurt and could be used as an efficient delivery system for probiotics.     

Physical and sensory characteristics and probiotic survival in ice cream sweetened with various polyols

The effect of polyols (xylitol, erythritol, maltitol and isomalt) on physical and sensory properties of probiotic ice cream, as well as the survival of Bifidobacterium BB‐12 during freezing over 28 days of frozen storage, was investigated. The control sample of ice cream, sweetened with sugar, showed a lower pH and higher overrun than those sweetened with polyols. The viable bifidobacteria counts remained above 8 log cfu/g in all samples. The amount of erythritol added was not enough to obtain a similar sweetness as in control, but too high to get an ice cream with good textural properties.     

Preparation of Acid‐Resistant Microcapsules with Shell‐Matrix Structure to Enhance Stability of Streptococcus Thermophilus IFFI 6038

Microencapsulation is an effective technology used to protect probiotics against harsh conditions. Extrusion is a commonly used microencapsulation method utilized to prepare probiotics microcapsules that is regarded as economical and simple to operate. This research aims to prepare acid‐resistant probiotic microcapsules with high viability after freeze‐drying and optimized storage stability. Streptococcus thermophilus IFFI 6038 (IFFI 6038) cells were mixed with trehalose and alginate to fabricate microcapsules using extrusion. These capsules were subsequently coated with chitosan to obtain chitosan‐trehalose‐alginate microcapsules with shell‐matrix structure. Chitosan‐alginate microcapsules (without trehalose) were also prepared using the same method. The characteristics of the microcapsules were observed by measuring the freeze‐dried viability, acid resistance, and long‐term storage stability of the cells. The viable count of IFFI 6038 in the chitosan‐trehalose‐alginate microcapsules was 8.34 ± 0.30 log CFU g^?1 after freeze‐drying (lyophilization), which was nearly 1 log units g^?1 greater than the chitosan‐alginate microcapsules. The viability of IFFI 6038 in the chitosan‐trehalose‐alginate microcapsules was 6.45 ± 0.09 log CFU g^?1 after 120 min of treatment in simulated gastric juices, while the chitosan‐alginate microcapsules only measured 4.82 ± 0.22 log CFU g^?1. The results of the long‐term storage stability assay indicated that the viability of IFFI 6038 in chitosan‐trehalose‐alginate microcapsules was higher than in chitosan‐alginate microcapsules after storage at 25 °C. Trehalose played an important role in the stability of IFFI 6038 during storage. The novel shell‐matrix chitosan‐trehalose‐alginate microcapsules showed optimal stability and acid resistance, demonstrating their potential as a delivery vehicle to transport probiotics.     

Survival and Metabolic Activity of Microencapsulated Bifidobacterium longum in Stirred Yogurt

ABSTRACT: Live cells of Bifidobacterium longum, microencapsulated in K‐carrageenan, were added to stirred yogurt after fermentation (pH 4.6) and stored at 4.4 °C for 30 d. Cell enumeration indicated no decline of encapsulated cell number in yogurt samples, while there was significant reduction in nonencapsulated cell population (89.3% for B. longum B6 and 91.8% for B. longum ATCC 15708). Ion‐exchange high‐performance liquid chromatography showed comparable amounts of lactic and acetic acids in all samples, indicating little metabolic activity by bifidobacteria in experimental yogurts. Consumer sensory analysis of blackberry‐flavored yogurts revealed that samples containing encapsulated bifidobacteria had a grainy texture. Results suggested that microencapsulation protected bifidobacteria from the low pH of yogurt.     

Probiotication of foods: A focus on microencapsulation tool

BackgroundWith almost thirty years of application in field of probiotics, microencapsulation is becoming an important technology for sustaining cell viability during food production, storage and consumption as well as for the development of new probiotic food carriers. Potentiality of microcapsules in protecting probiotics along human digestive tract seems to be well established. Instead, the inclusion of probiotics into foods, also in microencapsulated form, poses still many challenges for the retention of their viability, being food intrinsic and extrinsic factors crucial for this item.Scope and approachWe collect the relevant literature concerning the use of microencapsulation for the inclusion of probiotics in traditional food vehicles such as milk derivatives and in novel food carriers that were grouped in bakery, meat, fruit and vegetable. Furthermore we intent to highlight within different food categories the main factors that act in challenging probiotics viability and functionality. What we aim is to establish how microencapsulation is effectively promising in the research and development of innovative probiotic foods.Key findings and conclusionsDespite the relevant improvements toward the broadening of probiotic food products and categories, additional efforts have to be attempted. For this purpose, development of easy to use, stable and cheap probiotic microcapsules could be an important key for industrial spreading of microcapsules. Also the monitoring of cell stability along the entire food production including a real storage period as well as the assessment of encapsulated probiotic metabolism are some topics that require additional investigations.     

Survival,growth characteristics and bioactive potential of Lactobacillus acidophilus in a soy‐based cream cheese

BACKGROUND: Soy‐based products have received much attention lately as dairy replacers and carriers for probiotics, without the cholesterol and lactose intolerance factors. We have previously developed a soy cream cheese product and would like to evaluate its suitability as a carrier for probiotic microorganisms. Soy cream cheese is commercially uncommon, while a probiotic soy cream cheese is yet to be available in the market. RESULTS: Five strains of probiotics were screened for their α‐galactosidase activity. Lactobacillus acidophilus FTCC 0291 showed the highest α‐galactosidase‐specific activity and was incorporated into soy cream cheese for a storage study of 20 days at 25 and 4 °C. L. acidophilus FTCC 0291 in soy cream cheese at both storage temperatures maintained a viability exceeding 10⁷ CFU g^?1 over storage. Oligosaccharide and reducing sugar analyses indicated that L. acidophilus FTCC 0291 was capable of utilizing the existing reducing sugars in soymilk and concurrently hydrolyzing the oligosaccharides into simpler sugars for growth. L. acidophilus FTCC 0291 also produced organic acids, leading to decreased pH. Under low pH and high organic acid concentration, the growth of total aerobes and anaerobes was significantly (P < 0.05) suppressed compared to the control. The hydrolysis of protein in soymilk produced essential growth factors such as peptides and amino acids that may have promoted the growth of L. acidophilus FTCC 0291 and the release of bioactive peptides with in vitro angiotensin I‐converting enzyme inhibitory activity. CONCLUSION: This study showed that soy cream cheese could be used as a carrier for probiotic bacteria, with potential antihypertensive property. Copyright © 2009 Society of Chemical Industry     

Ice Cream as a Vehicle for Incorporating Health‐Promoting Ingredients: Conceptualization and Overview of Quality and Storage Stability

Ice cream is a product with peculiar textural and organoleptic features and is highly appreciated by a very broad spectrum of consumers. Ice cream's structure and colloidal design, together with its low‐temperature storage, renders it a very promising carrier for the stabilization and in vivo delivery of bioactive compounds and beneficial microorganisms. To date, many applications related to the design and development of functional ice cream have been documented, including products containing probiotics, prebiotics, synbiotics, dietary fibers, natural antioxidants such as polyphenols, essential and polyunsaturated fatty acids, and low glycemic index blends and blends fortified with mineral or trace elements. In this review, promising strategies for the incorporation of innovative functional additives to ice cream through the use of techniques such as microencapsulation, nanoemulsions, and oleogels are discussed, and current insights into the implications of matrix, processing, and digestion on bioactive compounds in frozen dairy desserts are comprehensively reviewed, thereby providing a holistic overview of the current and emerging trends in this functional food sector.     

Microencapsulation of Lactobacillus rhamnosus GG by Transglutaminase Cross‐Linked Soy Protein Isolate to Improve Survival in Simulated Gastrointestinal Conditions and Yoghurt

Microencapsulation is an effective way to improve the survival of probiotics in simulated gastrointestinal (GI) conditions and yoghurt. In this study, microencapsulation of Lactobacillus rhamnosus GG (LGG) was prepared by first cross‐linking of soy protein isolate (SPI) using transglutaminase (TGase), followed by embedding the bacteria in cross‐linked SPI, and then freeze‐drying. The survival of microencapsulated LGG was evaluated in simulated GI conditions and yoghurt. The results showed that a high microencapsulation yield of 67.4% was obtained. The diameter of the microencapsulated LGG was in the range of 52.83 to 275.16 μm. Water activity did not differ between free and microencapsulated LGG after freeze‐drying. The survival of microencapsulated LGG under simulated gastric juice (pH 2.5 and 3.6), intestinal juice (0.3% and 2% bile salt) and storage at 4 °C were significantly higher than that of free cells. The survival of LGG in TGase cross‐linked SPI microcapsules was also improved to 14.5 ± 0.5% during storage in yoghurt. The microencapsulation of probiotics by TGase‐treated SPI can be a suitable alternative to polysaccharide gelation technologies.     

Production of functional probiotic, prebiotic, and synbiotic ice creams

In this work, 3 types of ice cream were produced: a probiotic ice cream produced by adding potentially probiotic microorganisms such as Lactobacillus casei and Lactobacillus rhamnosus; a prebiotic ice cream produced by adding inulin, a prebiotic substrate; and a synbiotic ice cream produced by adding probiotic microorganisms and inulin in combination. In addition to microbial counts, pH, acidity, and physical and functional properties of the ice creams were evaluated. The experimental ice creams preserved the probiotic bacteria and had counts of viable lactic acid bacteria after frozen storage that met the minimum required to achieve probiotic effects. Moreover, most of the ice creams showed good nutritional and sensory properties, with the best results obtained with Lb. casei and 2.5% inulin.     

Nonfermented ice cream as a carrier for Lactobacillus acidophilus and Lactobacillus rhamnosus

Efficiency of a nonfermented ice cream for delivering Lactobacillus acidophilus and Lactobacillus rhamnosus to consumers was evaluated. Both of the microorganisms survived at the populations of greater than 10⁷ CFU g^?1 during 12 weeks of storage at ?19 °C. Addition of the microorganisms had no significant effect on the overrun, viscosity, firmness and melting behaviour; it changed the acidity, pH and sensory properties of the finished product. Resistance to acid and sensitivity to bile of both bacteria were tested separately on fresh harvested cells before inoculation to ice cream and then on the frozen‐thawed cells after 12 weeks of cold storage in ice cream. Ice cream processing followed by cold storage reduced acid resistance of both bacteria at pH 2.5. Resistance to bile in L. rhamnosus was not affected in frozen‐thawed ice cream when compared to fresh cell, whereas resistance to bile in L. acidophilus appeared to be more susceptible to the process and cold storage.     

Dried Tomato‐Flavored Probiotic Cream Cheese with Lactobacillus paracasei

Abstract: A dried tomato‐flavored probiotic cream cheese (P) containing Lactobacillus paracasei Lpc‐37 was developed for the purpose of this study. The same product, but without probiotic addition (C) was used as control. Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris were used as lactic starter cultures. Chemical composition analyses and sensory tests were performed on days 1 and 7, respectively. Titratable acidity, pH value and L. paracasei population were determined every 7 d during the refrigerated storage (21 d) of the cream cheeses. The experiment and analyses were performed in triplicate, using standard methods. Probiotic population remained greater than 10⁷ CFU/g throughout the storage period, thereby characterizing the product as potentially probiotic. Cream cheeses C and P did not differ on the sensory tests, both obtaining good overall acceptance by the consumers, of which 82.6% stated that they certainly or probably would buy the product. Practical Application: Lactobacillus paracasei Lpc‐37 is a probiotic bacterium and clinical studies have shown that this microorganism beneficially affects its host. In general, dried tomato‐flavored products and cream cheese are products with good acceptance by the consumers. Thus, regular consumption of the probiotic cream cheese developed in this study may have positive effects on health and well being of people if incorporated into their diet.     

Microencapsulation of bacteria: A review of different technologies and their impact on the probiotic effects

Probiotic based products are associated with many health benefits. However, the main problem is the low survival of these microorganisms in food products and in gastrointestinal tract. Providing probiotics with a physical barrier is an efficient approach to protect microorganisms and to deliver them into the gut. In our opinion, microencapsulation is one of the most efficient methods, and has been under especial consideration and investigation. However, there are still many challenges to overcome with respect to the microencapsulation process. This review focuses mainly on the methodological approach of probiotic encapsulation including materials and results obtained using encapsulated probiotic in food matrices and different pathologies in animal models.Industrial relevanceThe inclusion of probiotics into food matrices is one of the most challenging lines of research in food technology. Probiotics in general, and some strains in particular, have a low resistance to different environmental conditions, such as oxygen, light or temperature. Thus, the protection and isolation of the microorganism from the food matrix and the environmental condition are crucial for the development of new probiotic food. In this sense, microencapsulation has gained an increasing interest, since it has been demonstrated that it could protect the bacteria not only during its production process but also during its incorporation into the food matrix, also with protective effects during storage. In conclusion, microencapsulation is of great interest since it could allow a wider application of probiotics in the food market, actually restricted to fresh or powder products.     

Stability of free and encapsulated Lactobacillus acidophilus ATCC 4356 in yogurt and in an artificial human gastric digestion system

The objective of this study was to determine the effect of encapsulation on survival of probiotic Lactobacillus acidophilus ATCC 4356 (ATCC 4356) in yogurt and during artificial gastric digestion. Strain ATCC 4356 was added to yogurt either encapsulated in calcium alginate or in free form (unencapsulated) at levels of 8.26 and 9.47 log cfu/g, respectively, and the influence of alginate capsules (1.5 to 2.5 mm) on the sensorial characteristics of yogurts was investigated. The ATCC 4356 strain was introduced into an artificial gastric solution consisting of 0.08 N HCl (pH 1.5) containing 0.2% NaCl or into artificial bile juice consisting of 1.2% bile salts in de Man, Rogosa, and Sharpe broth to determine the stability of the probiotic bacteria. When incubated for 2 h in artificial gastric juice, the free ATCC 4356 did not survive (reduction of > 7 log cfu/g). We observed, however, greater survival of encapsulated ATCC 4356, with a reduction of only 3 log cfu/g. Incubation in artificial bile juice (6 h) did not significantly affect the viability of free or encapsulated ATCC 4356. Moreover, statistically significant reductions (~1 log cfu/g) of both free and encapsulated ATCC 4356 were observed during 4-wk refrigerated storage of yogurts. The addition of probiotic cultures in free or alginate-encapsulated form did not significantly affect appearance/color or flavor/odor of the yogurts. However, significant deficiencies were found in body/texture of yogurts containing encapsulated ATCC 4356. We concluded that incorporation of free and encapsulated probiotic bacteria did not substantially change the overall sensory properties of yogurts, and encapsulation in alginate using the extrusion method greatly enhanced the survival of probiotic bacteria against an artificial human gastric digestive system.     

Stability and viability of synbiotic microgels incorporated into liquid,Greek and frozen yogurts

The viability of Lactobacillus acidophilus when co-encapsulated with fructooligosaccharides in alginate–gelatin microgels, for incorporation into liquid, Greek, and frozen yogurts, during storage and in vitro-simulated digestion was studied. Liquid yogurt provided the highest viability for the encapsulated probiotics during storage, followed by frozen and Greek formulations when compared to free probiotics, highlighting the influence of microencapsulation, yogurt composition, and storage conditions. Addition of up to 20% of probiotic (AG) and symbiotic (AGF) microgels did not cause significant changes in the liquid and frozen yogurts’ apparent viscosity (η_ap); however, it decreased η_ap for the Greek yogurt, indicating that microgels can alter product acceptability in this case. Both AG and AGF microparticles improved viability of cells face to gastric conditions for liquid and frozen yogurts, delivering cells in the enteric stage. Summarizing, liquid yogurt was the most appropriate for probiotic viability during storage, while frozen yogurt presented better protection along digestibility.     

Microencapsulation of Bifidobacterium bifidum F‐35 in reinforced alginate microspheres prepared by emulsification/internal gelation

Alginate microspheres containing Bifidobacterium bifidum F‐35 prepared by emulsification/internal gelation were reinforced by blending with pectin or starch or coating with chitosan or poly‐L‐lysine to provide extra protection for the strain. The influence of these treatments on the size of microspheres, encapsulation yield (EY) and protective effect of microencapsulation on the cells was studied. No difference was detected in EY with different types of reinforcement, which was approximately 43–50%. The mean diameter of reinforced alginate microspheres ranged from 117 to 178 μm, reaching a maximum value when starch was incorporated in the alginate matrix. It was observed that the protective effects varied with the type of reinforcement. However, chitosan‐coated alginate microspheres provided the best protection for microencapsulated cells in simulated gastrointestinal tract and during 1 month of storage at 4 °C, and this system could be the comparatively effective vector of bifidobacteria for intestinal delivery.     

Sensory acceptance and survival of probiotic bacteria in ice cream produced with different overrun levels

The effect of different overrun levels on the sensory acceptance and survival of probiotic bacteria in ice cream was investigated. Vanilla ice creams supplemented with Lactobacillus acidophilus were processed with overruns of 45%, 60%, and 90%. Viable probiotic bacterial counts and sensory acceptance were assessed. All the ice creams presented a minimum count of 6 log CFU/g at the end of 60 d of frozen storage. However, higher overrun levels negatively influenced cell viability, being reported a decrease of 2 log CFU/g for the 90% overrun treatment. In addition, it was not reported an influence about acceptability with respect to appearance, aroma, and taste of the ice creams (P > 0.05). Overall, the results suggest that lower overrun levels should be adopted during the manufacture of ice cream in order to maintain its probiotic status through the shelf life.