Annealing processing technique divergently affects starch crystallinity characteristic related to resistant starch content: a literature review and meta-analysis

Annealing is one of starch physical modification techniques that can increase resistant starch (RS) content. However, the effect of annealing on RS varies based on botanical sources. Starch crystal type and relative crystallinity are two important characteristics of starch. This study aimed to compare the influence of annealing on starch crystallinity and different starch crystal type (A, B and C) and investigate its effect on RS content by literature meta-analysis study. The literature review was carried out using 22 research articles and 101 data points. The result showed relative crystallinity increase from the highest changes to the lowest, respectively; C-type crystal (18.98%) followed by B (13.60%) and A-type crystal (8.17%). Meta-analysis study results showed a significant increase of RS content on starches with A-type crystal (SMD = 6.46; 95% CI: 3.22–9.70; P < 0.01) and a positive relationship between the degree of crystallinity and RS content after annealing modification.     

Effect of Fermentation on Antioxidant Properties of Red Cabbages

The influence of fermentation, natural and inoculated by two types of lactic acid bacteria (Lactobacillus plantarum ATCC 8014 and Lactobacillus acidophilus, NCFM), on antioxidant properties of red cabbages was determined and compared with those of their unfermented counterparts. Fermentation led to increased antioxidant activity, which was measured by using DPPH and TEAC method. Highest antioxidant activity was observed in red cabbages fermented with L. plantarum. The total content of phenolic compounds increased upon natural fermentation and was determined by the Folin–Ciocalteu method. Interestingly, in contrast to natural fermentation, for the red cabbages inoculated with L. plantarum and L. acidophilus, the total amount of phenolics increased slightly until day 7 of fermentation and gradually decreased for longer time of fermentation. Fermentation appears to decrease the level of total anthocyanins for all type of fermentation. Additionally, results of the HPLC analysis indicated the metabolism of phenolic compounds during the fermentation of red cabbages. Thus fermentation offers a tool to further increase the antioxidant potential of red cabbages.     

Effect of Lactic Acid Bacteria Fermentation on Rosmarinic Acid and Antioxidant Properties of in vitro Shoot Culture of Orthosiphon aristatus as a Model Study

In vitro shoot culture of Orthosiphon aristatus was selected as a model system for lactic acid bacteria (LAB) fermentation study. This in vitro plant was subjected to different types of LAB fermentations (Lactobacillus plantarum ATCC 8014 and Lactobacillus acidophilus NCFM) for a different time periods of 24, 48, and 72 h at 37^oC. The LAB fermentations consisted of solid state fermentations in a climatic incubator and liquid state of fermentations in a DCU fermenter system. The aim was to determine the effect of fermentation on antioxidant properties of the in vitro plant extract. Results indicate that all types of LAB fermentation decreased the level of rosmarinic acid and total phenolic compounds; however, a slight increase in total flavonoids and flavonols was observed in solid state fermentations samples. The highest reduction was obtained in the sample of liquid state fermentation inoculated with L. plantarum for a period of 72 h. The loss in rosmarinic acid and phenolics was concomitant with a loss of total antioxidant activity (DPPH, TEAC, and SOD-like activity). HPLC result confirmed that the longer fermentation was the greater reduction phenolic acids content was found. These results indicate LAB fermentation caused a decrease on antioxidant properties of in vitro shoot culture of Orthosiphon aristatus.     

The effect of annealing on resistant starch content of different crop types: a systematic review and meta-analysis study

The growing demand for functional foods with a high resistant starch content (per cent RS) could be met by annealing starch modification. Through a meta-analysis, this study sought to shed light on the effect of annealing on the resistant starch content of various crop types. Twenty-one studies published between 2000 and 2020 were selected and eighty data points were extracted to be analysed using meta-essential tools. Hedge’s d Standardised Mean Difference (SMD) was designated for the effect size approach. Resistant starch content was influenced by the botanical origin of the carbohydrate source and the annealing parameters such as moisture content, incubation time and temperature. According to a meta-analysis of the data collected, the most significant increase in per cent RS is perceived on cereal (SMD: 7.58; 95% CI: 2.88–12.29; P = 0.001). Further analysis revealed that normal wheat had the highest significant per cent RS increase (SMD: 41.56; 95% CI: 19.52–63.61; P = 0.001). Annealing parameters resulted in significant %RS increase were moisture content of 80%, incubation time of 24 h and incubation temperature of 50–54 °C. These results were expected to provide data to optimise per cent RS increase through annealing efficiently.     

Improvement of Antioxidant Activities in Red Cabbage Sprouts by Lactic Acid Bacterial Fermentation

In the present study, the influence of three types of lactic acid bacteria (Lactobacillus plantarum ATCC 8014, Lactobacillus acidophilus NCFM, Danisco, and Lactobacillus rhamnosus GG E522 (ATCC 53103)) on antioxidant activities of fermented red cabbage sprouts was determined and compared with those of their unfermented/control counterparts. The fermentation resulted in a significant increase (p < 0.05) of antioxidant functionalities as measured by four assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging, Trolox equivalent antioxidant capacity (TEAC), superoxide dismutase (SOD)-like, and β-carotene/linoleic bleaching. The most considerable shift in the antioxidant activities was observed after 24 h of fermentation. These increases were followed by a decrease in total phenolic compounds, anthocyanins, and L-ascorbic acid and by an increase in flavonoids, flavonols, and several phenolic acids (gallic, chlorogenic, caffeic, syringic, p-coumaric, trans-3-hydroxy-4-methoxycinnamic, and trans-o-hydroxycinnamic acid) content. The relationship between the antioxidant activities and the compositional changes in antioxidant compounds due to LAB fermentation was observed. Fermented red cabbage sprouts inoculated with L. plantarum had the highest antioxidant activities (DPPH scavenging: 70.92%; TEAC: 1.94 mM Trolox equivalent; SOD-like activity: 63.40%, and β-carotene/linoleic bleaching: 44.33%), which was almost two-fold higher than those of unfermented treatments. These results indicated that LAB fermentation could be applied as a method to improve the potent antioxidant activities of red cabbage sprouts.