Novel starch types

This thesis investigated molecular changes in potato starch achieved through targeted mutations in the starch synthesis pathway. CRISPR/Cas9 was used to induce mutations in starch branching enzyme genes (SBE), with or without mutations in granule bound starch synthase gene (GBSS). The resulting starch was characterised for molecular and functional attributes. Barley starch obtained through conventional cross-breeding was also characterised, to explore potential impacts of fructan synthesis changes on starch synthesis at composition and molecular structure level. Inducing mutations in all alleles of the SBEI and some alleles of the SBEII produced high-amylose starch, while inducing mutations in all alleles of both SBEs resulted in amylose-only starch. GBSS mutations alone yielded a waxy starch phenotype, while introducing GBSS mutations in SBEs mutated background led to non-waxy, low-amylose lines. Mutations in SBEI produced starch with unit chain distributions close to the native variety. Mutations in the GBSS produced starch with building blocks (BB) distribution resembling the native variety. Significant deviations to unit chain and BB distribution were observed when both SBEI and SBEII were mutated. Presence of high proportions of large BB elevated gelatinisation and retrogradation temperatures, while high proportions of short amylopectin chains lowered gelatinisation temperature. Potato lines with diverse genetic backgrounds exhibited variations in pasting profiles, influencing film-forming behaviour. Natural genetic variation-based conventional cross-breeding of barley produced starch with modified structures, as upregulated fructan synthesis resulted in starch with a high proportion of large BB. These novel insights into how alterations in starch synthesis pathway affect starch properties pave the way for tailored starch development

Plasmin, plasminogen, protein and somatic cells variation of bulk milk : impact of breed, milking system and production months

During a period of one year, milk samples were collected from 45 different farms in Northern Sweden. Plasmin (PL), plasminogen (PG), somatic cell count (SCC) and total protein (TP) content were investigated in bulk milk received at the dairy. The composition of bulk milk samples was related to major farm and production variables (breed, milking system and production months). SCC and TP were measured in whole milk while, PL and PG analyses were performed on serum fraction in duplicates obtained by ultracentrifugation of defatted milk. PL and PG derived activities were analyzed by spectrophotometric method using multi-mode microplate reader at 37°C. Urokinase (49.5 plough units) was used as PG activator to measure the total proteolytic activity of PL and PG. The PG derived activity was not influenced by the breed class. The farms having mixtures of breeds had higher (P 0.05) from the milking system and production month for the considered farms. SCC varied with breed, lowest SCC (P < 0.05) was reported for Swedish Red breed and highest (P < 0.05) was reported for mountain breeds. Higher (P < 0.05) SCC counts were observed in AMS farms compared to CMS farms. SCC varied slightly according to the production month. Lower (P < 0.05) TP content was recorded for mountain breeds than for Holstein, Swedish red and farms having mixture of breeds. Jersey breed showed higher (P < 0.05) TP content than other breeds. Higher (P < 0.05) bulk milk TP content was observed for CMS than AMS farms. The mean TP content varied (P < 0.05) with the production month, with higher amount in October, November and December than in June, July and August. There was no clear trend or correlation of PL activity and PG derived activity with bulk milk TP or SCC

Can Dawul Kurundu (Neolitsea involucrate) leaf extract be used as a plant-based stabilizer in set yoghurt production?

The incorporation of plant-derived stabilizers in food processing and preservation has gained considerable industrial interest. The leaf extract of Neolitsea involucrate, Dawul Kurundu (DK), has proven to be a potent plant-derived stabilizing agent in the food industry. However, the potential of utilizing DK leaf extract in the dairy industry has not yet been proven. Thus, the feasibility of incorporating DK leaf extract in set yoghurt production by assessing its physicochemical, sensory, proximate composition, minerals (calcium and phosphorous), and microbial (Escherichia coli, yeast, and mold) quality parameters during storage at 4 degrees C up to 21 days was assessed. DK leaf aqueous extracts of 0.4% w/v (T2), 0.6% w/v (T3), and 0.8% w/v (T4) were used for testing with the control sample, 0.6% gelatin (T1). Compared to T1, there were no differences in color, taste, texture, and mouthfeel in all DK leaf extract-incorporated yoghurts, demonstrating the suitability of using DK leaf extract to replace the gelatin. A decreasing pattern of pH value was observed during 21 days of the storage period in all treatments, whereas total titratable acidity increased significantly with time. Furthermore, the lowest syneresis value was obtained by T4, demonstrating ideal stabilizing properties at higher incorporation levels. The proximate, mineral, and microbial compositions of all treatments showed no significant difference compared to the control. Therefore, overall results revealed that the 0.8% w/v level of DK leaf extract incorporation (T4) could be used as a potent stabilizer in set yoghurt production by allowing the possibility of replacing the gelatin without compromising its organoleptic properties. Improved and efficient methods for extracting the DK leaf extracts by focusing on their potential functional and health effects should be further examined

Development and characterization of biocomposite films using banana pseudostem, cassava starch and poly(vinyl alcohol): A sustainable packaging alternative

To meet the need for sustainable packaging, we introduce a novel biocomposite film consisting of banana pseudostem, cassava starch, and poly(vinyl alcohol). We aimed to evaluate the optimal biocomposite film composition, which is characteristic for packaging materials. Using the solvent casting method, we produced biocomposite films with varying proportions (10-40 % w/w) of the lignocellulosic component from both Sour and Ash Plantain banana pseudostems. The resulting biocomposite films were characterized for mechanical, chemical, thermal, water absorption, gas permeability, and morphological properties. At the 25 % lignocellulosic level, a notable drop (P < 0.05) in tensile strength and elongation was observed, while water absorption increased, and gas permeability decreased. Fourier Transform Infrared Spectroscopy analysis revealed insights into the structural attributes of lignocellulosic composites. Thermogravimetric analysis indicated an onset temperature of 120 degree celsius for thermal degradation, confirming the biocomposite's thermal stability. A fundamental discovery emerged with the optimal composition at a 30 % pseudostem powder inclusion, offering an exceptional balance of tensile strength, elongation at break, water absorption, and gas permeability. This breakthrough holds significant implications for eco-friendly biocomposite films, particularly in food packaging. Future work may be undertaken to further explore banana pseudostems' potential in creating biocomposite films with advanced functionalities and their broader applications, including characterizations

GBSS mutations in an SBE mutated background restore the potato starch granule morphology and produce ordered granules despite differences to native molecular structure

Potato starch with mutations in starch branching enzyme genes (SBEI, SBEII) and granule-bound starch synthase gene (GBSS) was characterized for molecular and thermal properties. Mutations in GBSS were here stacked to a previously developed SBEI and SBEII mutation line. Additionally, mutations in the GBSS gene alone were induced in the wild-type variety for comparison. The parental line with mutations in the SBE genes showed a - 40 % increase in amylose content compared with the wild-type. Mutations in GBSS-SBEI-SBEII produced non-waxy, low-amylose lines compared with the wild-type. An exception was a line with one remaining GBSS wild-type allele, which displayed -80 % higher amylose content than wild-type. Stacked mutations in GBSS in the SBEI-SBEII parental line caused alterations in amylopectin chain length distribution and building block size categories of whole starch. Correlations between size categories of building blocks and unit chains of amylopectin were observed. Starch in GBSS-SBEI-SBEII mutational lines had elevated peak temperature of gelatinization, which was positively correlated with large building blocks

Recent Advances in Starch-Based Blends and Composites for Bioplastics Applications

Environmental pollution by synthetic polymers is a global problem and investigating substitutes for synthetic polymers is a major research area. Starch can be used in formulating bioplastic materials, mainly as blends or composites with other polymers. The major drawbacks of using starch in such applications are water sensitivity and poor mechanical properties. Attempts have been made to improve the mechanical properties of starch-based blends and composites, by e.g., starch modification or plasticization, matrix reinforcement, and polymer blending. Polymer blending can bring synergetic benefits to blends and composites, but necessary precautions must be taken to ensure the compatibility of hydrophobic polymers and hydrophilic starch. Genetic engineering offers new possibilities to modify starch inplanta in a manner favorable for bioplastics applications, while the incorporation of antibacterial and/or antioxidant agents into starch-based food packaging materials brings additional advantages. In conclusion, starch is a promising material for bioplastic production, with great potential for further improvements. This review summarizes the recent advances in starch-based blends and composites and highlights the potential strategies for overcoming the major drawbacks of using starch in bioplastics applications

Quality parameters of natural phenolics and its impact on physicochemical, microbiological, and sensory quality attributes of probiotic stirred yogurt during the storage

Physicochemical, microbiological, and organoleptic properties were evaluated for probiotic stirred yogurts with plant pigments; 10% Hibiscus, 4% Turmeric, 6% Spinach, and 4% Blue pea, over 14 days at 4. compared to the colorless control. The color of yogurts were stable without sedimentation or adverse effect on physicochemical or sensory properties, although an increase of L* value observed over the storage. The microbial analysis confirmed the viability of probiotics (>9 logs CFU/mL) in all yogurts over the storage. Turmeric added yogurt resulted in the highest b* value, total phenolic content (72.6 mg GAE/L) and sensory score for color, while spinach added yogurt ranked the lowest in flavor at the end of storage. Results demonstrated the color stability of studied plant pigments in stirred yogurt with varying physicochemical and sensory properties. Addition of natural colorant in yogurt is recommended. Improved methods for extracting pigments and their health effects should be further examined

High fructan barley lines produced by selective breeding may alter beta-glucan and amylopectin molecular structure

Six cross-bred barley lines developed by a breeding strategy with the target to enhance the fructan synthesis activity and reduce the fructan hydrolysis activity were analyzed together with their parental lines, and a reference line (Gustav) to determine whether the breeding strategy also affected the content and molecular structure of amylopectin and beta-glucan. The highest fructan and beta-glucan content achieved in the novel barley lines was 8.6 % and 12 %, respectively (12.3-fold and 3.2-fold higher than in Gustav). The lines with low fructan synthesis activity had higher starch content, smaller building blocks in amylopectin, and smaller structural units of beta-glucans than the lines with high-fructan synthesis activity. Correlation analysis confirmed that low starch content was associated with high amylose, fructan, and beta-glucan content, and larger building blocks in amylopectin

Fecal Short-Chain Fatty Acid Ratios as Related to Gastrointestinal and Depressive Symptoms in Young Adults

Objective: Short-chain fatty acids (SCFAs) are produced by the gut microbiota and may reflect health. Gut symptoms are common in individuals with depressive disorders, and recent data indicate relationships between gut microbiota and psychiatric health. We aimed to investigate potential associations between SCFAs and self-reported depressive and gut symptoms in young adults.Methods: Fecal samples from 164 individuals (125 were patients with psychiatric disorders: mean [standard deviation] age = 21.9 [2.6] years, 14% men; 39 nonpsychiatric controls: age = 28.5 [9.5] years, 38% men) were analyzed for the SCFA acetate, butyrate, and propionate by nuclear magnetic resonance spectroscopy. We then compared SCFA ratios with dimensional measures of self-reported depressive and gut symptoms.Results: Depressive symptoms showed a positive association with acetate levels (rho = 0.235, p =.003) and negative associations with both butyrate (rho = -0.195, p =.014) and propionate levels (rho = -0.201, p =.009) in relation to total SCFA levels. Furthermore, symptoms of diarrhea showed positive associations with acetate (rho = 0.217, p =.010) and negative associations with propionate in relation to total SCFA levels (rho = 0.229, p = 0-007). Cluster analysis revealed a heterogeneous pattern where shifts in SCFA ratios were observed in individuals with elevated levels of depressive symptoms, elevated levels of gut symptoms, or both.Conclusions: Shifts in SCFAs are associated with both depressive symptoms and gut symptoms in young adults and may have of relevance for treatment