Impact of different cryoprotectants on the survival of freeze-dried Lactobacillus rhamnosus and Lactobacillus casei/paracasei during long-term storage

2015 ◽  
Vol 6 (3) ◽  
pp. 381-386 ◽  
Author(s):  
A. Jofré ◽  
T. Aymerich ◽  
M. Garriga

The production of long shelf-life highly concentrated dried probiotic/starter cultures is of paramount importance for the food industry. The aim of the present study was to evaluate the protective effect of glucose, lactose, trehalose, and skim milk applied alone or combined upon the survival of potentially probiotic Lactobacillus rhamnosus CTC1679, Lactobacillus casei/paracasei CTC1677 and L. casei/paracasei CTC1678 during freeze-drying and after 39 weeks of storage at 4 and 22 °C. Immediately after freeze-drying, the percentage of survivors was very high (≥94%) and only slight differences were observed among strains and cryoprotectants. In contrast, during storage, survival in the dried state depended on the cryoprotectant, temperature and strain. For all the protectants assayed, the stability of the cultures was remarkably higher when stored under refrigeration (4 °C). Under these conditions, skim milk alone or supplemented with trehalose or lactose showed the best performance (reductions ≤0.9 log units after 39 weeks of storage). The lowest survival was observed during non-refrigerated storage and with glucose and glucose plus milk; no viable cells left at the end of the storage period. Thus, freeze-drying in the presence of appropriate cryoprotectants allows the production of long shelf-life highly concentrated dried cultures ready for incorporation in high numbers into food products as starter/potential probiotic cultures.

Pharmaceutics ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 433 ◽  
Author(s):  
Tarun Ojha ◽  
Vertika Pathak ◽  
Natascha Drude ◽  
Marek Weiler ◽  
Dirk Rommel ◽  
...  

Poly(n-butyl cyanoacrylate) microbubbles (PBCA-MB) are extensively employed for functional and molecular ultrasound (US) imaging, as well as for US-mediated drug delivery. To facilitate the use of PBCA-MB as a commercial platform for biomedical applications, it is important to systematically study and improve their stability and shelf-life. In this context, lyophilization (freeze drying) is widely used to increase shelf-life and promote product development. Here, we set out to analyze the stability of standard and rhodamine-B loaded PBCA-MB at three different temperatures (4 °C, 25 °C, and 37 °C), for a period of time of up to 20 weeks. In addition, using sucrose, glucose, polyvinylpyrrolidone (PVP), and polyethylene glycol (PEG) as cryoprotectants, we investigated if PBCA-MB can be lyophilized without affecting their size, concentration, US signal generation properties, and dye retention. Stability assessment showed that PBCA-MB remain largely intact for three and four weeks at 4 °C and 25 °C, respectively, while they disintegrate within one to two weeks at 37 °C, thereby compromising their acoustic properties. Lyophilization analyses demonstrated that PBCA-MB can be efficiently freeze-dried with 5% sucrose and 5% PVP, without changing their size, concentration, and US signal generation properties. Experiments involving rhodamine-B loaded MB indicated that significant dye leakage from the polymeric shell takes place within two to four weeks in case of non-lyophilized PBCA-MB. Lyophilization of rhodamine-loaded PBCA-MB with sucrose and PVP showed that the presence of the dye does not affect the efficiency of freeze-drying, and that the dye is efficiently retained upon MB lyophilization. These findings contribute to the development of PBCA-MB as pharmaceutical products for preclinical and clinical applications.


1999 ◽  
Vol 62 (7) ◽  
pp. 808-810 ◽  
Author(s):  
MARISA S. GARRO ◽  
GRACIELA F. de VALDEZ ◽  
GUILLERMO OLIVER ◽  
GRACIELA S. de GIORI

The refrigerated shelf life of soymilk fermented with single cultures of Lactobacillus fermentum, L. casei, Streptococcus salivarius subsp. thermophilus, and Bifidobacterium longum was evaluated. During storage at 4°C for 28 days, the stability of the microflora differed markedly among the starter cultures. After 28 days, the average numbers of S. salivarius subsp. thermophilus decreased by two log cycles to 6.0 × 107 CFU/ml, whereas those of L. casei increased gradually by more than two log cycles to 4.6 × 109 CFU/ml. Numbers of B. longum and L. fermentum remained moderately high (8.7 × 108 CFU/ml and 3.7 × 108 CFU/ml, respectively) even after 28 days of storage. S. salivarius subsp. thermophilus and L. casei continued to metabolize sucrose during the storage period, but the pattern of consumption was different among the strains. The other starter cultures did not seem to have significant activity (P > 0.05) on the residual sugars. In most cases, L(+)-lactate predominated.


2015 ◽  
Vol 15 (1) ◽  
pp. 221-235 ◽  
Author(s):  
Magdalena Michalczyk ◽  
Ryszard Macura ◽  
Joanna Banaś ◽  
Iwona Tesarowicz ◽  
Ireneusz Maciejaszek

AbstractThis paper investigates the effect of adding oregano essential oil (0.02% v/w), freeze-dried garlic (1%), tomato concentrate (15%) and a combination of all three (in the same concentrations) on the shelf life of minced pork meat. Vacuum-packed samples with additives and a control were stored at 6±1°C for 16 days. Sensory, microbiological and biochemical changes were analysed over the whole storage period. The beneficial effect of oregano essential oil was generally to inhibit lipid oxidation, although its effect on bacterial growth was very weak. Adding tomato concentrate, combined with other additives, slowed the rate of microbiological and sensory changes, but had a marked effect on changes in proteins (SDS-PAGE analysis) and the proportion of meat pigments. The addition of freeze-dried garlic did not cause a substantial reduction of detectable bacteria count. Adding a combination of all three additives resulted in a product with a distinctly longer shelf life.


1987 ◽  
Vol 110 ◽  
Author(s):  
Alans Rudolph ◽  
Lewis P. Stratton ◽  
Wayne K. Knoll ◽  
Sandra Bayne ◽  
Frances Ligler

AbstractFor any viable blood substitute, questions of long-term storage and shelf-life must be addressed. Recently, we have made great progress in improving the stability of the blood substitute, liposome encapsulated hemoglobin (LEH). We have concentrated our efforts on protecting LEH in solution and in the long-term preservation of LEH by lyophilization. In particular, we have been able to retard and in some cases, reverse the oxidative process of metHb formation in solution by the addition of antioxidants such as NADH and glutathione. We have been able to regenerate Hb preparations with 60% metHb by the addition of 10 mM NADH and glutathione. In these preparations addition of these antioxidants results in a decrease of metHb levels from 62% to 15% over the course of 12.5 days at 4°C. We have also explored the use of protective solutes such as the disaccharide trehalose in the preservation of LEH in the freeze-dried state. Addition of increasing amounts of trehalose and other disaccharides results in the inhibition of lyophilization-induced fusion events and in the retention of hemoglobin within the unilamellar liposomal vesicles following rehydration.


Food Research ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 964-975
Author(s):  
A.S.L. Sulabo ◽  
M.E.L. Villasanta ◽  
K.G. Hermo ◽  
R.A. Lascano ◽  
L.S. Collado ◽  
...  

Development of an active starter culture is essential in the production of safe and highquality fermented foods. Freeze-drying is an effective microbial cell immobilization technology intended to produce active and stable starter cultures for long-term storage. To determine the influence of various drying medium formulations with mung bean powder and disaccharides on the viability of L. plantarum S20 during freeze-drying and subsequent storage at 6±2°C and 30±1°C, three treatments of drying medium consisting of mung bean powder without disaccharides (MBP), MBP with 5% (w/v) trehalose (MBP+T), and MBP with 5% (w/v) sucrose (MBP+T) were evaluated. Results showed that L. plantarum S20 viability after freeze-drying ranged from 9.56 to 10.03 log (CFU/g) with viability loss ranging from 0.20 to 0.51 log (CFU/g), with MBP being the least effective (p<0.05) in minimizing viability loss. Supplementing MBP with either 5% sucrose or 5% trehalose improved (p<0.05) survival of freeze-dried L. plantarum S20; and both disaccharides exhibit similar (p>0.05) cryoprotective effects on L. plantarum S20 during freeze-drying and subsequent storage. Storage at 6±2°C for 180 days resulted in significant decreases of 2.15, 2.17, and 3.27 log (CFU/g) in L. plantarum S20 population in MBP+T, MBP+S, and MBP, respectively. A more drastic decline [>6.0 Log (CFU/g)] in L. plantarum S20 population was observed in freeze-dried culture stored at 30±1°C for 60 days. Fermentation characteristics of freeze-dried L. plantarum S20 in mung bean slurry were also determined. Freeze-dried L. plantarum S20 in MBP with 5% (w/v) sucrose was able to acidify mung bean slurry from pH 6.8 to pH 3.8 after 8 hrs with maximum LAB population of 9.2 log (CFU/mL). Acidification of mung bean slurry by fresh culture (non-freeze-dried) on the other hand was relatively slower where pH dropped from 6.8 to pH 3.72 after 24 hrs. Current work suggested that lyophilized L. plantarum S20 could be used as a starter culture for mung bean-based fermentations but further research on this area is needed.


Author(s):  
N. S. Chervyakova ◽  
T. V. Valova ◽  
A. V. Osin

By the example of Martin Christ Epsilon 2-6D device carried out was assessment of the possibility to use freeze-dryers of the chamber type for conservation of pathogenic microorganisms collection strains. Elaborated was algorithm of lyophilisation of the III-IV pathogenicity groups bacteria, which incorporated conditions of freeze-drying and biological safety provision of this process. Indices of viability and survivability were defined for freeze-dried cells of pathogenic bacteria strains. Using thermostability test calculated were predicted timelines of storage of collection strains preparations freeze-dried in the flasks in Martin Christ Epsilon 2-6D. It was determined that in the collections of pathogenic microorganisms freeze-dryers of the chamber type could be used most prospectively for the III-IV pathogenicity groups bacteria conservation requiring mass reproduction and not intended for long storage. At the same time their application for freeze-drying of the strains of the I-II pathogenicity groups bacteria intended for a long storage, requires further adaptation of these devices as regards biological safety provision and prolongation of the shelf life.


2010 ◽  
Vol 4 (1) ◽  
pp. 72-81
Author(s):  
Abdul Wahed Baker ◽  
Zaid A. A. ◽  
Amer A. A.

The study included manufacturing of fermented dairy products by using full cream milk of four kinds of mammalian: (Buffalos, Cows, Sheep's and Goats); with the use of Lactobacillus casei as a starter for the production of fermented dairy products which had the ability to lower cholesterol percentage in the above mentioned products by (71.4, 70, 74.8 and 67.7)% respectively. The viability of Lb. casei had not been affected significantly during storage shelf life of 21days " The product shelf life " , keeping their therapeutic properties unaltered with high viable number of bacteria at time of consumption. The viable counts of the bacteria after storage period for manufactured products were (1.06× 109, 8.1× 108, 7.5× 108and 8× 108) CFU/ml respectively. These numbers represent a decrease equal to one logarithmic cycle for each of manufactured products of Cows, Sheep's and Goats milk, and the decrease of bacteria's viability of manufactured products of Buffalos milk was less than one logarithmic cycle. Results of statistical analysis showed that there was highly significant differences (P<0.05) in the viable bacterial cells counts between manufactured products. By sensory comparison of the manufactured fermented products together, the results shows that the manufactured products from Buffalos milk was the best then the manufactured products of Cows milk then Sheep's milk then goats milk


Foods ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 244 ◽  
Author(s):  
Alexandra Galetović ◽  
Francisca Seura ◽  
Valeska Gallardo ◽  
Rocío Graves ◽  
Juan Cortés ◽  
...  

The interest of the food industry in replacing artificial dyes with natural pigments has grown recently. Cyanobacterial phycobiliproteins (PBPs), phycoerythrin (PE) and phycocyanin (PC), are colored water-soluble proteins that are used as natural pigments. Additionally, red PE and blue PC have antioxidant capabilities. We have formulated a new food prototype based on PBP-fortified skim milk. PBPs from Andean cyanobacteria were purified by ammonium sulfate precipitation, ion-exchange chromatography, and freeze-drying. The stability of PE and PC was evaluated by changes in their absorption spectra at various pH (1–14) and temperature (0–80 °C) values. Purified PBPs showed chemical stability under pH values of 5 to 8 and at temperatures between 0 and 50 °C. The antioxidant property of PBP was confirmed by ABTS (2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical ion scavenging, and FRAP (Ferric Antioxidant Power) assays. The absence of PBP toxicity against Caenorhabditis elegans was confirmed up to 1 mg PBP/mL. Skim milk fortified with PE obtained a higher score after sensory tests. Thus, a functional food based on skim milk-containing cyanobacterial PBPs can be considered an innovative beverage for the food industry. PBPs were stable at an ultra-high temperature (138 °C and 4 s). PBP stability improvements by changes at its primary structure and the incorporation of freeze-dried PBPs into sachets should be considered as alternatives for their future commercialization.


2019 ◽  
Vol 25 (7) ◽  
pp. 608-617 ◽  
Author(s):  
Osman Gul ◽  
Ilyas Atalar ◽  
Latife Betul Gul

In this study, the effects of various matrices consisting of maltodextrin and reconstitute skim milk and their binary and ternary mixtures with gum Arabic in the microencapsulation of Lactobacillus casei Shirota by freeze-drying technique were assessed. Microcapsules produced with reconstitute skim milk showed high viability (>99%) after freeze drying. While the free cells were completely inactivated after exposure to simulated gastrointestinal conditions, the survival rates of microencapsulated L. casei Shirota were found high for all microcapsules except for maltodextrin and maltodextrin:gum Arabic formulas. The viability of microencapsulated L. casei Shirota during storage at refrigerate and room temperatures decreased between 0.39 and 2.43 log cycles and microcapsules produced with reconstitute skim milk:gum Arabic was found more durable at the both storage conditions. Reduction in the number of free cells was higher than encapsulated L. casei Shirota numbers during production of dessert, however the viability of encapsulated L. casei Shirota was found stable for 14 days of storage and consequently desserts containing encapsulated L. casei Shirota (except maltodextrin) showed stable pH values. This study revealed that combination of reconstitute skim milk:gum Arabic was an effective wall matrix for microencapsulation of L. casei Shirota by freeze drying and also very resistant against gastrointestinal fluids and storage conditions in view of protection of L. casei Shirota.


2015 ◽  
Vol 34 (4) ◽  
Author(s):  
Shaikh Adil ◽  
Sudhakar Changade ◽  
Anant Dhotre ◽  
Santosh Chopde

The objective of this study was evaluation of the shelf life of reconstituted <italic>kheer</italic> packed in previously sterilized cups and stored at 10± 1°C for 3 days. During period of studies the samples were examined for sensory evaluation after the first, second and third day using five treatments T1 (Pumpkin flesh <italic>kheer</italic>), T2 (1 per cent pumpkin powder + 43 per cent skim milk powder), T3 (2 per cent pumpkin powder + 42 per cent skim milk powder), T4 (3 per cent pumpkin powder + 41 per cent skim milk powder) and T5 (4 per cent pumpkin powder + 40 per cent skim milk powder). Samples were studied for sensory properties <italic>viz</italic>. colour, flavour, body texture, appearance and overall acceptability. Statistical analysis for shelf life studies revealed that both the treatments and storage period had significant effect on sensory qualities of the product. The scores for colour, flavour, body and texture, appearance and overall acceptability of all <italic>kheer</italic> samples decreased with the advancement of storage period. The rate of decline in the flavour score of T3 was more as compared to all other treatments. The score for T3 was (7.12) on first day which dropped to (6.05) on third day. The rate of decrease of scores for body and texture was more in treatment T5 than T1, T2, T3 and T4. There was a statistically significant difference in the appearance of reconstituted <italic>kheer</italic> samples for all the treatments on the day of preparation. The difference between all treatments was non-significant on second and third day of storage. The overall acceptability for T1, T2, T3, T4 and T5 samples decreased with the progress of storage period.


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