•Attention on mannitol production by fermentation is received in recent years.•Fermentation factors affected the mannitol yield are listed.•Mannitol applications in food, pharmaceutical and chemical industries are reviewed.Mannitol is a polyol or an alditol that is naturally found in many plants and can be produced by several microorganisms. Based on its beneficial physiological effects, mannitol is currently used as a functional sweetener in the food industry. In addition, mannitol has applications in pharmaceutical, chemical and medical industries because of its promising advantages. Mannitol can be produced by extraction, chemical synthesis, or fermentation. Certain mutants have been constructed for different purposes. In this review, we focused on recent advances in the applications and biotechnological production of mannitol.

A novel strain, SK26.001, which can produce mannitol from a high concentration of glucose without the addition of fructose, was isolated from sugarcane juice. This strain was identified as Candida parapsilosis based on 18S ribosomal RNA (rRNA) sequence analysis and the morphological and physiological-biochemical characteristics of the strain. Under optimized fermentation conditions, the mannitol concentration in shake flasks reached 68.5 g/L. When batch fermentation was performed, the fed glucose was completely consumed after 72 h, resulting in a final mannitol concentration of 80.3 g/L. Fed-batch fermentation was then performed with glucose feed. During the fed-batch process, ammonia water was added to maintain the pH at 4.0. The mannitol concentration in the fermenter reached 97.1 g/L after 120 h, with a total glucose consumption of 284 g/L.

•The pentapeptide from chickpea protein, a good source of natural compound.•It could up-regulate several antioxidant enzyme activities in cells.•It could up-regulate the expression of several genes mediated by Nrf2.•It could be functional food ingredient and natural antioxidant.The effects of an antioxidative pentapeptide from chickpea protein hydrolysates on oxidative stress in Caco-2 and HT-29 cell lines were investigated. The bioactive pentapeptide had an amino acid sequence of Asn–Arg–Try–His–Glu (NRYHE). Caco-2 and HT-29 cells were pretreated with peptide (0.05, 0.1, 0.25 and 0.5 mg/mL) for 2 h and stimulated with 1 mM H2O2 for 6 h. The activity of three important antioxidative enzymes, catalase, glutathione reductase and glutathione peroxidase, increased in a concentration-dependent manner. It was observed that peptide treatment elevated the expression of Nrf2 mRNA and several relative genes NQO1, HO-1, γ-GCS regulated by Nrf2 compared to the positive control. The trends in HT-29 and Caco-2 cells were similar.

An antioxidant peptide was purified using consecutive chromatographic methods from chickpea protein hydrolysates (CPH). This peptide was designated as Fra.7. It had a molecular weight of 717.37 Da, and its amino acid sequence was identified as Asn-Arg-Tyr-His-Glu by an ABI 4700 proteomics analyser. This antioxidant peptide was identified for the first time from food-derived protein hydrolysates. The molar ratio of the five amino acids in the sequence was 1:1:1:1:1. This antioxidant peptide efficiently quenched the free radical sources 1,1-diphenyl-2-pycryl-hydrazyl (DPPH), hydroxyl, and superoxide free radicals. The Cu2+ and Fe2+ chelating activities were 76.92% and 63.08% at the peptide concentration of 50 μg mL−1, respectively. Furthermore, the inhibition of the Fra.7 on lipid peroxidation was greater than that of α-tocopherol. The inhibition ratio of the linoleic acid autooxidation was 88.81% at the eighth day of analysis.Research highlights► A new antioxidant peptide was purified from chickpea protein hydrolysates. ► The amino acid sequence of Fra.7 is Asn-Arg-Tyr-His-Glu. ► Fra.7 has high antioxidant and metal ion chelating activities.