Oxidative stress in probiotic Petit Suisse: Is the jabuticaba skin extract a potential option?

What are the main obstacles to turning foods healthier through probiotics incorporation? a review of functionalization of foods by probiotics and bioactive metabolites

Functional foods are gaining significant attention from people all over the world. When added to foods, probiotic bacteria can turn them healthier and confer beneficial health effects, such as improving the immune system and preventing cancer, diabetes, and cardiovascular disease. However, adding probiotics to foods is a challenging task. The processing steps often involve high temperatures, and intrinsic food factors, such as pH, water activity, dissolved oxygen, post-acidification, packaging, and cold storage temperatures, can stress the probiotic strain and impact its viability. Moreover, it is crucial to consider these factors during food product development to ensure the effectiveness of the probiotic strain. Among others, techniques such as microencapsulation and lyophilization, have been highlighted as industrial food functionalization strategies. In this review, we present and discuss alternatives that may be used to functionalize foods by incorporating probiotics and/or delivering bioactive compounds produced by probiotics. We also emphasize the main challenges in different food products and the technological characteristics influencing them. The knowledge available here may contribute to overcoming the practical obstacles to food functionalization with probiotics.

Probiotic bacilli incorporation in foods: is really so easy?

Foods containing probiotic bacilli spores are becoming more and more popular because of their resistance to acidic pH, low water activity, and, most importantly, heat processes. Even though spores may engage in some functions, such as immunomodulation, the majority of the beneficial characteristics are unique to vegetative cells. As matter of fact, the development of foods fortified with spores ought to even ensure the germination of the spores along the gastrointestinal tract. In this perspective, vegetative cells derived from spore germination were separately counted on a minimal medium because the traditional approach is based on the use of complex media that allows the spores to germinate independently by stimuli arising from processing or digestion. In more detail, three Bacillus spp. cultures with claimed probiotic properties were added to two entirely unrelated foods (pasta and croissants), and tolerance, as well as germination, was monitored before and after exposure to simulated GIT, as well as at the beginning and end of the products shelf life. For the first time, potential probiotic bacilli were included in a frozen ready-to-bake product. Germination appears to be prevented in this instance, and the impact of baking, matrix and cold storage on spores was examined independently. All of the parameters appeared to contribute, although further research is needed due to the unpredictable behavior exhibited by spores during freezing.

Production and Evaluation of Yogurt Colored with Anthocyanin-Rich Pigment Prepared from Jabuticaba (Myrciaria cauliflora Mart.) Skin

Yogurt is known as a healthy food, but some synthetic additives that are commonly added to it can be one of the factors that restricts yogurt’s consumption. The aims of this study were to prepare and evaluate yogurts with the addition of spray-dried, anthocyanin-rich colorant extracted from jabuticaba (Myrciaria cauliflora Mart.) skin. The concentrated extract was spray-dried using maltodextrin (20 g/100 g w/w) as a carrier and added to yogurts in the concentrations of 0.5, 1.0, 1.5, and 2.0 g/100 g w/w. The yogurts were stored for up to 28 days under refrigeration and periodically evaluated. Except for the yogurts to which 1.5 g of extract was added, all samples had a slight pH reduction in the first 7 days of storage. Throughout the yogurts’ storage period, the anthocyanin and a* values were slightly reduced (p < 0.05), indicating some anthocyanin instability. The rheological behavior was typical for yogurts, but the casein gel network was probably disrupted by the jabuticaba extract incorporation, reducing the yogurt’s apparent viscosity. Panelists showed good acceptance for the attributes of taste, color, aroma, appearance, texture, and overall impression, indicating that this natural pigment has the potential to be a substitute synthetic color additive for the production of mixed berry yogurts, contributing to the reduction of waste.

Jaboticaba berry: A comprehensive review on its polyphenol composition, health effects, metabolism, and the development of food products

Jaboticaba, a popular Brazilian berry, has been studied due to its relevant polyphenol composition, health benefits and potential use for the development of derived food products. Considering that around 200 articles have been published in recent years, this review aims to provide comprehensive and updated information, as well as a critical discussion on: (i) jaboticaba polyphenolic composition and extraction methods for their accurate determination; (ii) jaboticaba polyphenol's metabolism; (iii) biological effects of the fruit and the relationship with its polyphenols and their metabolites; (iv) challenges in the development of jaboticaba derived products. The determination of jaboticaba polyphenols should employ hydrolysis procedures during extraction, followed by liquid chromatographic analysis. Jaboticaba polyphenols, mainly anthocyanins and ellagitannins, are extensively metabolized, and their metabolites are probably the most important contributors to the relevant health effects associated with the fruit, such as antioxidant, anti-inflammatory, antidiabetic, hepatoprotective and hypolipidemic. Most of the technological processing of jaboticaba fruit and its residues is related to their application as a colorant, antioxidant, antimicrobial and source of polyphenols. The scientific literature still lacks studies on the metabolism and bioactivity of polyphenols from jaboticaba in humans, as well as the effect of technological processes on these issues.

Encapsulation of Bifidobacterium BB12® in alginate-jaboticaba peel blend increases encapsulation efficiency and bacterial survival under adverse conditions

Most foods with probiotics claims are associated to dairy products, whose consumption is restricted to part of the population, creating a favorable scenario for the development of probiotic foods in alternative matrices. However, the development of probiotic foods in non-dairy matrices is still a technological challenge, since the foods intrinsic parameters can cause injuries to microorganisms. An alternative to protect the microbial cells in adverse environments involves encapsulation. Therefore, the objective of this study was to evaluate the influence of alginate-jaboticaba peel blend in the improvement of encapsulation efficiency, viability maintenance, and cell survival of Bifidobacterium BB12® under simulated gastrointestinal digestion and after incorporating in traditional jaboticaba jam. The particles were obtained by ion gelling technique using alginate with or without powdered jaboticaba peel. The addition of jaboticaba peel in particles improved encapsulation efficiency (> 90%) and resulted in higher cell survival in simulated gastrointestinal digestion. During storage in jam, the loss in cell viability was approximately constant: c.a. 0.5 log CFU/g/day for encapsulated cells and c.a. 1.0 log CFU/g/day for free cells. These results suggest that use of alginate and powdered jaboticaba peel blend is a promising approach to protect Bifidobacterium BB12® against adverse environments, such as non-dairy food matrices. KEY POINTS: • Powdered jaboticaba peel increased the encapsulation efficiency in alginate particles. • Encapsulation improved cell survival under adverse conditions. • Useful approach for the development of non-conventional probiotic products. Graphical abstract.

Chemopreventive Properties of Extracts Obtained from Blueberry (Vaccinium myrtillus L.) and Jabuticaba (Myrciaria cauliflora Berg.) in Combination with Probiotics

The association of probiotics and fruit extracts may influence the chemopreventive effect of colorectal cancer. In this context, antiproliferative activity was evaluated to select the best extracts that would be added probiotics, after addition of Bifidobacterium or Lactobacillus in the extracts the antiradical and antioxidant activity, quinone reductase (QR) assay and apoptosis assay were evaluated. Four extracts were isolated: E1: rich in total phenolic compounds; E2: rich in water-soluble phenolic compounds; E3: rich in most apolar phenolic compounds and E4: rich in anthocyanins. The antiproliferative results showed that the best extracts for blueberry and jabuticaba were, respectively the extract E4 and E2. After addition of the probiotic bacteria in these best extracts, it was observed that E2 from jabuticaba presented significantly higher antiradical and antioxidant activity values compared to E4 from blueberry before and after addition of probiotics. There was also a 9-fold increase in activity of QR by the E2 from jabuticaba with Lactobacillus (JL). Likewise, this same extract showed a significant increase both in apoptotic and necrotic cells for both cells. In conclusion, extract rich in water-soluble phenolic compounds (E2) from jabuticaba presented a greater chemopreventive effect compared to the others.

Impact of post fermentation cooling patterns on fatty acid profile, lipid oxidation and antioxidant features of cow and buffalo milk set yoghurt

Background

In the manufacturing of set yoghurt, after reaching 4.6 pH, post fermentation cooling is applied to stop the bacterial activity. Depending upon the required textural and flavor attributes, one phase and two phase cooling patterns are accordingly selected. In one phase cooling, temperature of the yoghurt is rapidly decreased below 10 °C using blast freezing and then it is gradually dropped to 4-5 °C. In two phase cooling, temperature of yogurt is rapidly decreased to less than 20 °C and then it is gradually decreased to 4-5 °C. These cooling phases have a significant impact on textural and flavor perspectives of yoghurt. It is necessary to study the impact of industrially adopted cooling patterns on fatty acid profile, antioxidant characteristics, lipid oxidation and sensory characteristics of cow and buffalo milk set yoghurt.

Methods

This experiment was organized in a completely randomized design and every treatment was replicated five times to minimize the variation. Whole cow and buffalo milk without any standardization were converted to set yoghurt (400 g cups) using Strepotococcus thermophillus and Lactobacillus bulgaricus as starter bacteria. After reaching 4.6 pH, cow and buffalo yoghurt samples were exposed to three different cooling patterns. In first trial, samples of cow and buffalo yoghurt were cooled from 43 °C to 25 °C in 1 h and finally cooled to 4-5 °C in another hr. (T₁). In second trial, samples were cooled from 43 °C to 18 °C in 1 hr. and finally cooled down to 4-5 °C in another 1 h. (T₂). In third trial, samples were cooled from 43 °C to 4-5 °C in 2 h (T₁). Alteration in fatty acid profile, total antioxidant capacity, reducing power, free fatty acids, peroxide value, conjugated dienes, vitamin A, E, color and flavor of cow and buffalo yoghurt samples were assessed for 20 days at the frequency of 10 days.

Results

All the three cooling patterns had a non-significant effect on compositional attributes of yoghurt. Buffalo milk yogurt had higher percentage of fat, protein and total solids than yoghurt prepared from cow milk (p < 0.05). At zero day, DPPH free radical scavenging activity of T₂ and T₃ was significantly higher than T₁. This may be due to the longer exposure of T₁ at relatively higher temperature than T₂ and T₃. Effect of storage period up to 10 days was non-significant in T₂ and T_3. Reducing power of cow and buffalo milk yoghurt was also significantly affected by the cooling patterns applied. Reducing power of T₂ and T₃ was considerably higher than T₁ (p < 0.05). At zero-day, total antioxidant capacity of cow and buffalo milk yoghurt in T₃ was 42.6 and 61.4%, respectively. At zero day, total antioxidant capacity of T₂ and T₃ was significantly higher than T₁. Effect of storage on total antioxidant capacity of T₂ and T₃ remained non-significant till 10 days of storage. At zero day, the impact of cooling patterns on fatty acid profile of T₁, T₂ and T₃ was non-significant, whereas, storage period had a marked impact on fatty acid profile. After 10 days, T₁ was considerably different in fatty acids from T₂ and T₃. After 10 days of storage of cow milk yoghurt in T₁, concentration of C_4:0, C_6:0, C_8:0, C_10:0, C_12:0, C_14:0, C_16:0, C_18:0, C_18:1 and C_18:2 decreased by 0.1, 0.11, 0.09, 0.07, 0.21, 0.38, 0.28, 0.27, 0.44 and 0.06%, respectively. Cow milk yoghurt in T₁ after 10 days of storage, concentration of C_4:0, C_6:0, C_8:0, C_10:0, C_12:0, C_14:0, C_16:0, C_18:0, C_18:1 and C_18:2 decreased by 0.07, 0.15, 0.04, 0.17, 0.20, 0.34, 0.27, 0.36 and 0.04%, respectively. After 10 days of storage in T₂ and T₃, loss of fatty acids was 1.2 and 3.61% from C_4:0 to C_10:0, respectively. Milk type had no effect on peroxide value of yoghurt. Cooling of cow and buffalo yoghurt from 43 °C to 25 °C had a pronounced effect on peroxide value. At zero day, peroxide values of cow and buffalo yoghurt in T₁ were 0.32 and 0.33 (MeqO₂/kg). At zero day, peroxide value of cow and buffalo yoghurt in T₂ were 0.24 and 0.26 (MeqO₂/kg). At zero day, peroxide value cow and buffalo yoghurt in T₃ were 0.23 and 0.25 (MeqO₂/kg). Cooling patterns i.e. from 43 °C to 25, 18 and 5 °C (T₁, T₂ and T₃) had a significant effect on the amount of vitamin A and E. Concentration of vitamin A and E in T₁ were significantly less than T₂ and T₃. Cooling patterns had a significant effect on texture, T₁ had a thick texture with higher viscosity as compared to T₂ and T₃. Thickness of yoghurt was in the order of T₁ > T₂ > T₃ with no difference in color and flavor score till 10 days of storage.

Conclusion

Results of current investigation indicated that milk type and post fermentation cooling patterns had a pronounced effect on antioxidant characteristics, fatty acid profile, lipid oxidation and textural characteristics of yoghurt. Buffalo milk based yoghurt had more fat, protein, higher antioxidant capacity and vitamin content. Antioxidant and sensory characteristics of T₁ were optimum till 10 days of storage.

The Step of Incorporation of Bacillus coagulans GBI-30 6086 Into "requeijão cremoso" Processed Cheese Does Not Affect Metabolic Homeostasis of Rats

Dairy product consumption is a common habit in Brazil. These products present a good matrix for probiotic incorporation. Thus, in this study the feasibility of producing a probiotic “requeijão cremoso” incorporated with Bacillus coagulans GBI-30 6086 in three different steps and its metabolic effect in an animal model for 2 weeks has been evaluated. Wistar adult health rats were randomized into one to five groups (n = 8 for each group): Control (C); “requeijão cremoso” without probiotic (RC); probiotic inoculated in the milk before pasteurization at 65°C/30 min (RPP); “requeijão cremoso” inoculated before the fusion step and consequently exposed to 90°C/5 min (RPF); and “requeijão cremoso” inoculated after fusion step, i.e., once the product temperature reached 50°C (RPAF). At the end of treatment, analysis of molecular markers of proteins of stress and antioxidant system, HSP 25, 60, 70 and 90, SOD and catalase were performed in the animals’ muscles by Western Blot technique. The HSP25, HSP90 and catalase levels of C, RPP, RPF, and RPAF were similar, indicating that the homeostasis remained unchanged. The incorporation of B. coagulans GBI-30 6086 in the “requeijão cremoso” was shown to be stable and the microorganism remained viable in all steps tested. The incorporation of the probiotic strain in the fusion stage facilitated the technological process, since it allowed a better homogenization of the product and did not affect the maintenance of the metabolic homeostasis of rats.

Behavior of different Bacillus strains with claimed probiotic properties throughout processed cheese ("requeijão cremoso") manufacturing and storage

Even though spore-forming bacteria have been mainly linked to spoilage or foodborne pathogens vehiculated through foods, some strains of Bacillus can potentially present probiotic properties. The advantage of incorporating probiotic Bacillus strains in foods relies mainly on the fact that these microorganisms present high resistance to harsh processing conditions. "Requeijão cremoso" is a type of processed cheese highly appreciated in Brazil. During processing, this product is submitted to several harsh conditions (heating at 90 °C, for instance), leading to the inactivation of probiotic bacteria belonging to Lactobacillus and Bifidobacterium genera. That fact has precluded the development of probiotic "requeijão cremoso" products; however, probiotic Bacillus strains may comprise a promising alternative to overcome the low resistance of traditional probiotics to food processing. The objective of this study was to evaluate the behavior of different Bacillus strains with claimed probiotic properties throughout processed cheese ("requeijão cremoso") manufacturing. A total of five different Bacillus strains with claimed probiotic properties (B. coagulans MTCC 5856, B. coagulans GBI-30 6086, B. subtilis PXN 21, B. subtilis PB6, and B. flexus HK1) were individually inoculated at different stages of manufacture - curd pasteurization, coagulation, and fusion - of "requeijão cremoso" and their survival in each of these stages was determined. The survival of B. coagulans GBI-30 6086 was further assessed throughout "requeijão cremoso" production and shelf life (45 days at 6 °C). Besides, the chemical composition, level of proteolysis, and fatty acid profile of the treatments during shelf life were evaluated. The fusion stage was found as the most appropriate for the addition of B. coagulans GBI-30 6086, which allows the production of probiotic "requeijão cremoso" and facilitates the technological process while preventing the occurrence of final product recontamination.

The resistance of Bacillus, Bifidobacterium, and Lactobacillus strains with claimed probiotic properties in different food matrices exposed to simulated gastrointestinal tract conditions

The resistance of Bifidobacterium, Lactobacillus, and Bacillus strains with claimed probiotic properties in different food matrices was evaluated. Lactobacillus paracasei PXN 37, Lactobacillus acidophilus La-5, Bifidobacterium animalis subsp. lactis Bb-12, Bifidobacterium breve PXN 25, Bacillus subtilis PXN 21, Bacillus coagulans GBI30 6086 and Bacillus coagulans MTCC 5856 strains were inoculated in "requeijão cremoso" cheese, pasteurized orange juice, and bread. Further, the counts of the strains with claimed probiotic properties were determined throughout the products' shelf-life. Additionally, the survival (%), at the beginning and at the end of their shelf-life, of each strain with claimed probiotic properties inoculated in the three foods was estimated by using a static in vitro system simulating the gastric (pH 2), enteric I (pH 5) and enteric II (pH 7) phases of gastrointestinal tract (GIT). Overall, it has been found that the Bacillus strains with claimed probiotic properties showed greater viability than probiotic Bifidobacterium and Lactobacillus strains no matter the food studied. The percentage of survival of the Bacillus strains with claimed probiotic properties were always above 83%. The Bacillus strains with claimed probiotic properties were able to survive well in all the food matrices tested. Therefore, this study shows that these strains of Bacillus may comprise a feasible strategy for expanding the range of "probiotic food" choices given their high resistance to the composition of foods, manufacturing steps, and resistance to simulated GIT conditions.

Fermented Dessert with Whey, Ingredients from the Peel of Jabuticaba (Myrciaria cauliflora) and an Indigenous Culture of Lactobacillus plantarum: Composition, Microbial Viability, Antioxidant Capacity and Sensory Features

The use of agro-industrial wastes in combination with indigenous lactic acid bacteria is an interesting option to confer functional potential to food products. The microbial viability, chemical composition, antioxidant capacity, texture and sensory acceptability of a fermented dairy dessert containing the indigenous culture Lactobacillus plantarum CNPC003, whey and ingredients obtained from the jabuticaba (Myrciaria cauliflora) peel were compared with formulations without lactobacilli (control) or containing a commercial probiotic culture (Lactobacillus rhamnosus LR32). L. plantarum presented viability higher than 7 log CFU g-1 in the dessert, as did the commercial probiotic, for 21 days at 4 ± 1 °C. Total phenolic contents (45⁻60 mg gallic acid equivalents, GAE, 100 g-1) were comparable to those of other studies evaluating dairy products containing plant sources. The formulations were low in fat, presenting as acceptable for overall consumption, with attractive color and appreciable texture. Considering the total antioxidant capacity, 200⁻250 g of dessert would be necessary to capture 1 g of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The dessert with Lactobacillus plantarum CNPC003 is seen as a viable alternative for the use of whey and jabuticaba peel, as well as a potential functional food due to the concentration of lactobacilli reached, besides the presence of antioxidant phenolic compounds.

Chemical composition and hypocholesterolemic effect of milk kefir and water kefir in Wistar rats

ABSTRACT Objective To compare the effects of fermented kefir on the nutritional, physiological, and biochemical parameters of rats. Methods Grains of milk kefir (whole and skimmed) and water kefir (brown sugar) were used. The chemical composition analysis was performed on substrates and fermented beverages. The rats were evaluated for weight gain, body mass index, as well as their food, water, kefir, and calorie intake. We also evaluated their energy efficiency coefficient, weight of organs, in addition to their serum, and hepatic biochemistry. Results Fermentation increased the acid content index owing to degradation of lactose and brown sugar. The animals consumed more kefir, reducing the intake of chow and water. Kefir did not alter body and organ weight, while improving the lipid profile. Conclusion Water kefir with brown sugar was more effective in improving the lipid profile.

Functionalization of yogurts with Agaricus bisporus extracts encapsulated in spray-dried maltodextrin crosslinked with citric acid

Mushroom extracts contain bioactive compounds potentially useful to functionalize foodstuffs. Herein, alcoholic extracts of Agaricus bisporus were studied for their bioactivity and viability as functional ingredients in a food product with high water content (yogurt). Extracts were microencapsulated (to improve their stability and hydrophilicity) by spray-drying, using maltodextrin crosslinked with citric acid as encapsulating material. The effect of thermal treatment (after atomization) on crosslinking and bioactivity of microspheres was tested. The incorporation of free and thermally untreated forms resulted in yogurts with higher initial antioxidant activity (EC₅₀ values: 214 and 272 mg.mL^-1) that decreased after 7 days (EC₅₀ values: 248 and 314 mg.mL^-1). Contrarily, thermally treated microencapsulated extracts showed higher antioxidant activity after the same period (EC₅₀ values, 0 days: 106 mg.mL^-1; 7 days: 48.7 mg.mL^-1), in result of an effective protection provided by microencapsulation with crosslinked maltodextrin and citric acid. Functionalized yogurts showed an overall maintenance of nutritional properties.

Epigallocatechin-3-gallate

Purpose

The purpose of the study was to explore the possibility of utilization of epigallocatechin-3-gallate (EGCG) as a novel preservative in cheese. EGCG has strong antioxidant and antimicrobial properties and may be commercially exploited as a natural antioxidant and preservative in cheese like products which are highly susceptible to lipid oxidation.

Design/methodology/approach

The study was conducted to evaluate the possibility of using EGCG as a natural antioxidant and preservative in cheese. Kalari, a hard and dry cheese, was used as a model and treated with different concentrations of EGCG (0, 0.05 and 0.10 per cent) and aerobically packaged within low-density polyethylene pouches and assessed for oxidative stability and storage quality under refrigerated (4 ± 1°C) conditions.

Findings

EGCG showed a significant (p < 0.05) effect on the lipid oxidative stability as the treated products exhibited significantly (p < 0.05) lower thiobarbituric acid reactive substances (milligram malonaldehyde/kg) values. A significant (p < 0.05) effect was also observed on the microbiological characteristics of the products, as treated products showed significantly (p < 0.05) lower values for total plate count (log cfu/g), psychrophilic count (log cfu/g), yeast and mould count (log cfu/g) and free fatty acid (% oleic acid) values. Coliforms (log cfu/g) were not detected throughout the storage period. Significantly (p < 0.05) higher scores were observed for various sensory parameters of the treated products. EGCG successfully improved the oxidative stability and storage quality of Kalari.

Originality/value

The results suggest that EGCG might be useful to the dairy industry as an efficient alternative to synthetic antioxidants and preservatives.

Influence of lactose hydrolysis on galacto-oligosaccharides, lactose, volatile profile and physicochemical parameters of different yogurt varieties

BACKGROUND

Different types of reduced-lactose yogurt, obtained by lactose hydrolysis using β-galactosidase enzyme, are commercially available. The breakdown of lactose modifies the carbohydrate profile, including the production of prebiotic galacto-oligosaccharides (GOS), which could affect the survival and activity of starter and probiotic cultures and the parameters of yogurt quality. The extension of these changes is dependent on the yogurt matrix composition. This study aimed to evaluate the influence of lactose hydrolysis on GOS, lactose, volatile profile and physicochemical parameters of different yogurt varieties during storage.

RESULTS

The presence of β-galactosidase enzyme did not affect either the global composition or the survival of cultures. Overall, the hydrolyzed products had lower acidity than traditional ones. GOS were found at similar levels in fresh hydrolyzed yogurts, whereas in traditional yogurts they were not detected. The proportion of ketones, acids and aldehydes seems to be more dependent on yogurt variety than on addition of the enzyme. Likewise, the storage period affected the volatile fraction to different degree; the increase in acid compounds was more pronounced in hydrolyzed than in traditional yogurts.

CONCLUSION

This work shows that it is possible to obtain different varieties of reduced-lactose yogurt, some of them with additional benefits to health such as reduced fat, reduced calories, added with probiotic/inulin and enriched in GOS, with similar characteristics to traditional products. © 2016 Society of Chemical Industry.

Development and validation of a near infrared spectrophotometric method to determine total antioxidant activity of milk

In the present study a spectrophotometric method for the determination of total antioxidant activity (TAA) based on ABTS assay was developed and validated on raw milk (RM), whole UHT milk (WUM), partially skimmed UHT milk (SUM), whole pasteurised milk (WM) and partially skimmed pasteurised milk (SM). The most suitable solvent for antioxidant extraction was 80% acetone. Regardless of the type of milk, the coefficient of determination from the linearity test was greater than 0.95. The limit of detection ranged from 0.74 to 6.07μmoll^-1 Trolox equivalents. Repeatability, calculated as relative standard deviation of twenty measurements within a day, and reproducibility, calculated as relative standard deviation of sixty measurements across three days, ranged from 1.24 to 4.04% and from 2.18 to 3.52%, respectively. Preservative added to RM had negligible effects on the TAA of milk. The greatest TAA was measured for SM followed by SUM, RM, WM and WUM.

Effect of different thistle flower ecotypes as milk-clotting in Serra da Estrela cheese

Purpose

Thistle flower (Cynara cardunculus) aqueous extracts, as rich source of milk-clotting peptidases, have been widely used for cheeses marketed under the Registry of the Protected Designation of Origin, as it is the case of Serra da Estrela cheese, manufactured from raw ewes’ milk and without addition of any commercial starter culture. This paper aims at studying the influence of six different ecotypes of thistle flowers in cheese properties during the ripening and of final products.

Design/methodology/approach

Cheeses were produced with different thistle flower extracts and then the clotting time, weight and colour of cheeses, as well as texture properties and sensorial characteristics, were evaluated.

Findings

The clotting time varied from 47 to 66 min, and the weight loss along ripening varied between 32 and 40 per cent. There was some influence of thistle flower ecotype on the colour during ripening and in the final product. The results of texture analysis revealed significant differences between the thistle ecotypes: crust firmness varying from 2.4 to 5.6 N; inner firmness from 0.82 to 1.82 N; stickiness from −0.5 to −1.60 N; adhesiveness from −3.0 to −11.3 N.s; and Ecotype C was particularly distinguishable. Sensorial evaluation revealed differences among the cheeses, with Ecotype C receiving the highest score for global appreciation.

Originality/value

The usage of different extracts of thistle flower to produce Serra da Estrela cheese with different properties is a novelty, and it allows the possibility of manipulating this parameter in the future so as to produce cheeses with specific characteristics, addressed to different consumer targets.