Inoculation Of Starter Cultures Research Articles

Effects of Various Stabilizers on Sensorial Quality of Yoghurt

This research was aimed to preserve the yoghurts using stabilizers without refrigeration in terms of syneresis and sensory analysis. Yoghurts were prepared using three stabilizers viz., gelatin, carboxymethylcellulose and sodium alginate and a control (without stabilizer). For which set type yoghurt was prepared with 2% starter culture inoculation and was incubated at 43⁰C for 3 hours and was stored at 5-7⁰C. Statistical analysis of all the treatments showed that 0.2 % stabilizer containing samples were significantly superior (p<0.05). The best samples with stabilizers containing 0.2% were again compared with control. From this, 0.2% gelatin added sample had significantly superior (p<0.05) scores. Shelf life of the sample was observed and it was compared with control at refrigerated condition. Sensorial gelatin added sample was best up to eleventh days while the control was best up to seventh days. Gelatin added sample showed less syneresis compared to control and adding stabilizer seems slower the acid development and syneresis of yoghurt in terms of storage time.Sunsari Technical College Journal 2015,2(1):7-12

Effect of commercial starter cultures on physicochemical characteristics, microbial counts and free fatty acid composition of dry-cured foal sausage

Abstract The need for high-quality safe products has resulted in the use of starter cultures for the production of dry-cured sausages. The aim of this work was to evaluate the effect of commercial starter cultures on the physicochemical properties, microbiological counts and free fatty acid composition during the ripening of dry fermented foal sausages. Microbial counts revealed that, although initial counts of Enterobacteriaceae were similar in the four batches (3.48 log CFU/g), this microbial group exhibited a strong decrease during the ripening of inoculated sausages, and reached values below 1 log CFU/g in the final product, whereas the counts of Enterobacteriaceae in the control sausages were 2.41 log CFU/g at the end of the ripening. In general, physicochemical parameters were not affected by the use of starter cultures, but by the ripening time, with the exception of pH values, since the inoculation of starter cultures resulted in a stronger acidification during the first two weeks of production, with pH values below 5 in inoculated batches. Finally, statistical analysis revealed that free fatty acid (FFA) profile was not significantly affected by starter cultures and it might therefore be considered that the major release of FFA was probably due to endogenous lipases. In conclusion, it seems that the inclusion of starter cultures contributes to improve the hygienic quality of foal sausages without significant effect on lipolysis, texture and appearance.

Inoculation of starter cultures in a semi-dry coffee (Coffea arabica) fermentation process

The aim of this study was to evaluate the use of yeasts as starter cultures in coffee semi-dry processing. Arabica coffee was inoculated with one of the following starter cultures: Saccharomyces cerevisiae UFLA YCN727, S. cerevisiae UFLA YCN724, Candida parapsilosis UFLA YCN448 and Pichia guilliermondii UFLA YCN731. The control was not inoculated with a starter culture. Denaturing gradient gel electrophoresis (DGGE) was used to assess the microbial population, and organic acids and volatile compounds were quantified by HPLC and HS-SPME/GC, respectively. Sensory analyses were evaluated using the Temporal Dominance of Sensations (TDS). DGGE analysis showed that the inoculated yeasts were present throughout the fermentation. Other yeast species were also detected, including Debaryomyces hansenii, Cystofilobasidium ferigula and Trichosporon cavernicola. The bacterial population was diverse and was composed of the following genera: Weissella, Leuconostoc, Gluconobacter, Pseudomonas, Pantoea, Erwinia and Klebsiella. Butyric and propionic acids, were not detected in any treatment A total of 47 different volatiles compounds have been identified. The coffee inoculated with yeast had a caramel flavor that was not detected in the control, as assessed by TDS. The use of starter cultures during coffee fermentation is an interesting alternative for obtaining a beverage quality with distinctive flavor.

Pasting Properties of White Corn Flours of <i>Anoman</i> 1 and <i>Pulut Harapan</i> Varieties as Affected by Fementation Process

This research was aimed to evaluate the pasting properties of white corn flour made from Anoman 1 and Pulut Harapan varieties as affected by the fermentation process of the corn grits. The fermentation process studied were 1) spontaneous fermentation (SF); 2) fermentation with the addition of a complete starter culture at 0 hour (CC fermentation) and 3) fermentation of (CC) with additional inoculation of starter culture containing amylolytic microorganisms at 16 hours (AC fermentation). The evaluation of pasting properties was done on the flour made from corn grits fermented for 0, 36, 48, and 72 hours. Our results showed that pasting properties of corn flour of Anoman 1 and Pulut Harapan varieties were affected by fermentation process. Addition of starter culture in the fermentation showed more complex effect on the pasting properties and was a function of the fermentation time. Fermentation process of corn grits affected the pasting properties of the resulted flour, both for Anoman I and Pulut Harapan corn varieties. The differences in the effect of fermentation process on the pasting properties were due to the different amylose/amylopectin content. AC fermentation of corn grits could increase the stability of paste for flour containing higher amylose content but decrease the stability of paste for flour containing high amylopectin. Specifically, CC fermentation caused significant increase in the peak viscosity value especially for corn flour of Pulut Harapan. Fermentation for up to 48 h had resulted in corn flour of Pulut Harapan variety having a higher PV value, but it did not affect the tendency to retrograde.

Effect of different starter cultures on the biogenic amines production as a critical control point in fresh fermented sausages

The selection of critical control points is one of the most important steps in the design of a hazard analysis and critical control points system. In this study, the influence of starter culture inoculation on biogenic amine accumulation in fresh fermented sausage as critical control point was studied. The effect of three starter culture Lactobacillus plantarum plus Bifidobacterium lactis, L. plantarum plus Bifidobacterium bifidum or L. plantarum plus B. lactis and B. bifidum on amines production were investigated. Tyramine (TY), Cadaverine (CA), Putrescine (PU), Histamine (HIS) and Tryptamine (TR) contents increased during the fermentation and storage stage, and TY was the prevailing amine in the final product. Sausages produced by fermentation with starters, as compared to natural fermentation (control), had a lower amount of biogenic amine. A great reduction in biogenic amine content was achieved when Bifidobacterium sp. were inoculated, also levels of species of Enterobacteriaceae and Pseudomonas decreased, while lactic acid bacteria counts increased during fermentation and storage.

Development of Hazard Analysis Critical Control Points (HACCP) and Enhancement of Microbial Safety Quality during Production of Fermented Legume Based Condiments in Nigeria

Critical control points during production of iru and okpehe , two fermented condiments, were identified in four processors in Nigeria. Physical objects such as stone and metallic objects were mixed in with the seeds; contamination resulted from wet-dehulling by foot pressing and water used in washing. The pH variation during fermentation ranged from 6.9 – 8.5 for both unfermented cotyledon and fermented condiments. Total aerobic viable count (TAVC) ranged from 1.2 – 6.2 Log 10 CFU/g. Coliforms, enterococci, staphylococci and B. cereus were pathogens detected during processing and post-processing of condiments. This indicates that the processing of condiment using traditional method is subject to microbial contamination. Dry-dehulling, cooking under pressure and inoculation of starter cultures reduced contamination and enhanced safety quality. Training of processors about Hazard Analysis Critical Control Points (HACCP), processing, environmental sanitation and personal hygiene were suggested as strategies to improve the safety of these traditional fermented condiments.

Bacterial community analysis during fermentation of ten representative kinds of kimchi with barcoded pyrosequencing

Kimchi, a food made of fermented vegetables, is densely populated by indigenous microorganisms that originate from the raw ingredients under normal conditions. Most microbiological studies on kimchi have been on the most popular dish, baechu-kimchi (Chinese cabbage kimchi). Therefore, relatively little is known about the various other kinds of kimchi (depending on the region, season, main ingredient, starter culture inoculation and recipe). In this study, we collected 100 samples periodically during the fermentation of ten representative kinds of kimchi (including starter-inoculated kimchi) that were stored in the refrigerator (4 °C) during the 30−35 days fermentation period. The multiplex barcoded pyrosequencing of a hypervariable V1−V3 region of the 16S ribosomal RNA (rRNA) gene tagged with sample-specific barcodes for multiplex identifiers was employed for bacterial community profiling. We found that bacterial communities differed between starter-inoculated and non-inoculated kimchi at the early stages of fermentation, but overall there were no significant differences in the late phases. Also, the diversity and richness of bacterial communities varied depending on the various types of kimchi, and these differences could largely be explained by the major ingredients and the manufacture processes of each types of kimchi. This study provides the comprehensive understanding of the factors influencing the biodiversity of the kimchi ecosystem.

Biogenic amine formation in Nham, a Thai fermented sausage, and the reduction by commercial starter culture, Lactobacillus plantarum BCC 9546

Biogenic amines are of concern for sausage due to their toxicological effects on nervous, blood pressure, gastric and intestinal systems. In this study, the influence of raw pork meat quality and starter culture inoculation on biogenic amines accumulation in Nham, a Thai traditional fermented pork, were studied. Before Nham processing, pork meat was stored at 30°C for 6h, and at 4 and −20°C for 2days. Formation of biogenic amines (cadaverine, putrescine, histamine and tyramine) was significantly higher in Nham processed from stored meat. Accumulation of these biogenic amines in Nham reduced significantly by the addition of Lactobacillus plantarum BCC 9546, a commercial Nham starter culture. The results highlight the importance of using fresh meat products and the inclusion of an appropriate starter culture to minimise the formation of biogenic amines during the process of Nham fermentation.

Effect of starter culture inoculation on feed hygiene and microbial population development in fermented pig feed composed of a cereal grain mix with wet wheat distillers’ grain

Investigating the influence of an added starter culture on the properties of fermented liquid pig feed. Diets of cereal grain blended with wet wheat distillers' grain that were either not inoculated (WWDG), inoculated with a silage starter culture at start (WWDGsc1) or at start and at each backslopping (replacement of 80% the content with fresh mixture, simulating feed outtake, WWDGsc5) were fermented for 5 days, followed by 5 days of daily backslopping. Numbers of undesirable micro-organisms (enterobacteria, moulds) were reduced in all fermentations; particularly enterobacteria in the starter culture inoculated diets. Lactobacillus plantarum present in the starter culture became dominant in diets WWDGsc1 and WWDGsc5. However, Lactobacillus panis that was dominating WWDG was also abundant in WWDGsc1 and WWDGsc5. Yeast populations were not influenced by the starter culture, with Pichia fermentans dominating all fermentations. All diets had similar chemical characteristics with the exception of a significant increase of all tested organic acids in WWDGsc5. The addition of a starter culture influences the bacterial population in fermented liquid feed, but there is also a strong impact of the flora already present in the feed ingredients. The yeast population is not influenced by adding a lactic acid bacteria (LAB) starter culture. A consortium of LAB and yeast strains adapted to the fermentation should be used as starter culture. The results suggest that it is possible to influence the current unpredictable and spontaneous process of feed fermentation when appropriate starter cultures are used. For this purpose, LAB and yeasts with desirable characteristics should be isolated.

Effect of the inoculation of a starter culture and vacuum packaging during the resting stage on sensory traits of dry-cured ham

The effects of the inoculation of a mixed starter culture and vacuum packaging (during resting stage) on odour, appearance, texture and flavour of dry-cured ham were studied. After salting, half of the 36 processed hams were inoculated with a commercial starter culture containing lactic-acid bacteria, Gram-positive catalase-positive cocci and yeasts. Nine hams per group (inoculated and non-inoculated) remained vacuum-packaged during resting. External odour during the process, as well as appearance of the cut surface, texture and flavour on semimembranosus and biceps femoris of the final product were assessed. Vacuum packaging during resting caused an increase in white film and feedstuff flavour, as well as a decrease in aged flavour, hardness, fibrousness and overall liking. The use of the starter culture brought about an increase in feedstuff flavour, a decrease in sweetness, aged flavour, nutty flavour and overall liking and, only in vacuum-packaged hams, the development of a floral flavour, but had no significant effect on texture descriptors. The starter culture studied is considered inappropriate for the production of traditional Spanish dry-cured ham regardless of the type of resting used.

DETERMINATION OF OPTIMUM FERMENTATION QUALITY OF CAPERS (CAPPARIS OVATA DESF. VAR. CANESCENS) IN DIFFERENT BRINE CONDITIONS

ABSTRACT Lactic acid, citric acid, yogurt and starter culture (Lactobacillus plantarum) inoculation were tested singly in brines for the fermentation of raw caper buds (Capparis ovata Desf. var. canescens). The buds were divided into two different sizes, small and big, according to their diameters before fermentation, and the effects of bud size on the fermentation were also investigated. Ten percent salt containing brine was evaluated as the control brine. Small buds could be recommended for their higher acidity levels and hardness scores. Citric and lactic acid addition revealed very low pH values (2.14–2.60) and high acidity levels (1.2–1.7%). Starter culture inoculation or yogurt addition to the brine resulted in lower acidity values, similar to the control brine. Lactic and citric acid addition not only accelerated the acidification rate, but also decreased the growth in the brine during fermentation. The differences between flavor and color scores of samples were not statistically significant from the bud size point of view, while these differences were significant for hardness scores (P < 0.01). The best initial brine conditions deduced from the physicochemical, microbiological and sensory results were citric acid and lactic acid added brine types. PRACTICAL APPLICATIONS In many of the fermented foods, the biological and microbiological bases of the fermentation processes are still poorly understood. Ensuring increased shelf life and microbial safeness of foods by fermentation is a fairly complex process and requires some information. Caperbush is native to the Mediterranean region where the plant is still grown commercially. Recently, there has been an increased interest in capers and demand for their processed buds, which increases its place throughout the world market. Thus, the different media for optimum fermentation of the caper buds are compelling for the producers to improve microbial safety and contribute to the pleasant sensory profile of the end product. The selection criteria of the optimum fermentation media for the large-scale industrial production should take account of the substrate, technical properties of the additives and strain, food safety requirements and quality expectations. The high glucosinolate content of caper buds and glucocapparin and glucocleomin, which are peculiar to this plant, make it a different substrate from the other vegetables and fruits. Addition of organic acids, particularly citric and lactic, revealed good results in the product. Yogurt as a starter of lactic fermentation in brine is promising for use in industrial large scale production from the economical point of view.

Effect of stabilizers on the physico-chemical and sensory attributes of thermized yoghurt

Stabilized thermized yoghurt was produced by the addition of gelatin, carboxyl methyl cellulose (CMC) and corn starch, into yoghurt mix as stabilizers, each at 0, 0.5, 0.75 and 1.0% concentrations. The yoghurt samples produced after pasteurization of the mix, cooling, inoculation of starter culture and incubation for about 16 h were thermized at 75oC for 60 s followed by immediate cooling. Results show that titratable acidity value of the control samples (0% stabilizer) was 0.92 ± 0.03. CMC, when added to yoghurt mix at levels of 0.5% and above, depressed lactic acid production (compare 0.92 ± 0.03 of the control with 0.90 ± 0.01 of samples containing 0.5 and 0.75% CMC). This observation is in contrast to effects of corn starch and gelatin which enhanced lactic acid production (at least up to 0.75% concentration). This was also mirrored (in reverse order) in the pH values; as samples with higher titratable acidity had, expectedly, lower pH values. Addition of stabilizers decreased percent protein and ash contents due to dilution effect but increased total solids and specific gravity of the thermized yoghurt samples. Sensory results showed that addition of corn starch produced the most desirable flavour and taste which differed significantly (p < 0.05) from flavour and taste produced by gelatin but did not differ significantly (p ≥ 0.050) from that produced by CMC at 0.5 and 0.75% concentrations. Yoghurt containing CMC had the best mouth feel/consistency as well as appearance which did not differ significantly (p ≥ 0.05) from the mouth feel and appearance of yoghurt containing corn starch but differed significantly from yoghurt containing gelatin. Yoghurt containing CMC at 0.75% concentration was the most generally accepted. Key words: Stabilizers, thermized yoghurt, sensory attribute, physco-chemical.

Effect of stabilizers on the physico-chemical and sensory attributes of thermized yoghurt

Stabilized thermized yoghurt was produced by the addition of gelatin, carboxyl methyl cellulose (CMC) and corn starch, into yoghurt mix as stabilizers, each at 0, 0.5, 0.75 and 1.0% concentrations. The yoghurt samples produced after pasteurization of the mix, cooling, inoculation of starter culture and incubation for about 16 h were thermized at 75oC for 60 s followed by immediate cooling. Results show that titratable acidity value of the control samples (0% stabilizer) was 0.92 ± 0.03. CMC, when added to yoghurt mix at levels of 0.5% and above, depressed lactic acid production (compare 0.92 ± 0.03 of the control with 0.90 ± 0.01 of samples containing 0.5 and 0.75% CMC). This observation is in contrast to effects of corn starch and gelatin which enhanced lactic acid production (at least up to 0.75% concentration). This was also mirrored (in reverse order) in the pH values; as samples with higher titratable acidity had, expectedly, lower pH values. Addition of stabilizers decreased percent protein and ash contents due to dilution effect but increased total solids and specific gravity of the thermized yoghurt samples. Sensory results showed that addition of corn starch produced the most desirable flavour and taste which differed significantly (p Yoghurt containing CMC had the best mouth feel/consistency as well as appearance which did not differ significantly (p
0.05) from the mouth feel and appearance of yoghurt containing corn starch but differed significantly from yoghurt containing gelatin. Yoghurt containing CMC at 0.75% concentration was the most generally accepted.

Aminogenesis control in fermented sausages manufactured with pressurized meat batter and starter culture

The application of high hydrostatic pressure (200 MPa) to meat batter just before sausage fermentation and the inoculation of starter culture were studied to improve the safety and quality of traditional Spanish fermented sausages (fuet and chorizo). Higher amounts of biogenic amines were formed in chorizo than in fuet. Without interfering with the ripening performance in terms of acidification, drying and proteolysis, hydrostatic pressure prevented enterobacteria growth but did not affect Gram-positive bacteria significantly. Subsequently, a strong inhibition of diamine (putrescine and cadaverine) accumulation was observed, but that of tyramine was not affected. The inoculated decarboxylase-negative strains, selected from indigenous bacteria of traditional sausages, were resistant to the HHP treatment, being able to lead the fermentation process, prevent enterococci development and significantly reduce enterobacteria counts. In sausages manufactured with either non-pressurized or pressurized meat batter, starter culture was the most protective measure against the accumulation of tyramine and both diamines.

Application of molecular techniques in wine microbiology

Wine fermentation is a complex microbiological process in which yeasts predominate. It is long debated whether yeasts occurring on the surface of grapes or the resident yeasts on the winery equipment play the primary role in conducting the fermentation. The origin, development, changes and succession of various yeast species can be followed using specific molecular techniques allowing the differentiation and typing of yeast strains. Techniques such as pulsed field gel electrophoresis of chromosomal DNA, restriction fragment length polymorphism analysis, and polymerase chain reaction (PCR)-based methods have recently been employed in studying the microbiology of wine making. These shed new light on the dynamics of fermentation started spontaneously or directed by the inoculation of starter cultures.